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This paper analyses the importance of the South Central Andean High Puna megapatch, above 4000 masl, in the history of late Pleistocene exploration and colonization of the Atacama Desert, including the contrasting habitats that exist towards the hyperarid Pacific Ocean coast or the ecosystems bordering the tropical forests, on the western and eastern sides of the Andes, respectively. These ecosystems, which were firmly established by the end of the Pleistocene, are examined as key factors in the history of human peopling. The social, demographic and climate conditions associated with the peopling processes are discussed in relation to the appropriate technological, subsistence and settlement strategies developed by pioneer populations, who for their initial settlement selected highly productive patches where water and fauna converged. Based on concepts derived from metapopulation theory, all relevant archaeological paleoecological data from both sides of the Andean Cordillera are presented and discussed. It is concluded that the pioneer occupation of the high Puna megapatch was a gradual process, related to an emergent Andean human mobility system that connected a wide range of altitudinally staggered habitats. Moreover, we suggest that divergent cultural trajectories evolved since the early Holocene, affecting highland, lowland and coastal habitats. [ABSTRACT FROM AUTHOR]

No es una novedad que el crecimiento de las poblaciones urbanas está aumentando, especialmente en zonas de bajos recursos. Dicho crecimiento viene acompañado de servicios de saneamiento ambiental deficientes y falta de recursos para el almacenamiento adecuado del agua, lo que ha favorecido el crecimiento de la población de mosquitos y, por ende, la propagación del dengue. El dengue es una enfermedad viral transmitida principalmente por los mosquitos Aedes aegypti que constituye uno de los mayores problemas de salud pública. El análisis cualitativo y cuantitativo de la propagación de esta enfermedad es de suma importancia para la sociedad, pues permite plantear un plan de choque para la prevención de una epidemia. Presentamos el análisis de un modelo metapoblacional del tipo SIR-SI que representa la dinámica del dengue para dos zonas conectadas por los tiempos de permanencia de la población humana en ellas, así como el análisis cualitativo del modelo, considerando diferentes escenarios de conexión entre las dos zonas estudiadas.

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Despite intensive management since the 1970s, recovery of the endangered northwestern Atlantic population of the Roseate Tern (Sterna dougallii dougallii) has not offset low productivity from a female-biased sex ratio, low adult survival, and habitat constriction. Now, >90% of individuals breed at three sites within 200 km from Long Island, NY, to Buzzards Bay, MA (warm-water subregion). To characterize the impact of historical bottlenecks, metapopulation structure, and demographic fluctuations on genetic variation, Roseate Terns from the warm-water (1870s, 1970s, 1997, 2016) and coldwater (Nova Scotia, Canada; 2018) subregions were genotyped at 8-16 microsatellites and 2-3 mitochondrial regions. Diversity declined in the warm-water subregion from the 1870s (expected heterozygosity [HE] = 0.44, allelic richness [AR] = 2.86) and 1970s (HE = 0.53, AR = 3.25) to 1997 (HE = 0.38, AR = 2.58). Genetic signatures of bottlenecks persisted in 1997 (P = <0.001-0.003) and 2016 (P = <0.001-0.005), but an increase in variation occurred by 2016 (HE = 0.50, AR = 2.85). Weak structure was detected between contemporary warm- and cold-water subregions (θ = 0.06) and within the warmwater subregion (θ = 0.04). Both demographic (3,439-3,821) and genetic (3,040) estimates suggested effective population size (Ne) stability over the last 100 years, despite large fluctuations in census size (4,000-8,662). Results suggest that 50 years of management (restoring habitat, preventing gull encroachment, controlling predators) at colony sites supported a small, stable Ne and maintained a hierarchical metapopulation that allowed gene flow to redistribute genetic variation throughout the northwest Atlantic. The metapopulation remains highly vulnerable to stochastic events but harbors resiliency and redundancy through gene flow and a stable Ne. For long-term persistence from a genetic perspective, managers must maintain the major source colonies, increase the availability of high-quality peripheral breeding sites, and protect concentrated nonbreeding sites that facilitate gene flow. [ABSTRACT FROM AUTHOR]

Introduction: Estimates of contemporary connectivity of the broadcast spawning coral Pocillopora verrucosa between multi-use marine protected areas (MUMPAs) are required to assess MUMPA effectiveness and their ability to enhance resilience against disturbances. Objective: To determine the genetic structure and connectivity patterns between P. verrucosa demes inside the Gulf of California and evaluate the role and effectiveness of established MUMPAS in their protection and resilience. Methods: We assessed P. verrucosa connectivity along its peninsular range (~350 km), including five locations and three MUMPAs in the Gulf of California using six microsatellite genetic markers. Results: Population structure was significant (FST = 0.108***) when demes included clonal replicates; however, when these clones were removed from the analysis, the sexual individuals comprised a metapopulation panmixia (FST = 0.0007 NS). To further understand connectivity patterns, an assignment test was carried out which identified ten recent between-deme migrants with a mean dispersal distance of 116.6 km (± 80.5 SE). No longdistance dispersal was detected. These results highlight the ecological importance of the Bahía de La Paz region, including Archipiélago de Espíritu Santo MUMPA. This region, located at the center of the species peninsular range, exports larva to downstream sink demes such as the Loreto (northwardly) and Cabo Pulmo (southwardly) MUMPAs. Of importance, inter-MUMPA spacing was larger than the mean larval dispersal by ~56 km, suggesting thar the designation of intermediate 'no-take' zones would enhance short-distance connectivity. Conclusion: This study contributes as a baseline for policymakers and authorities to provide robust strategies for coral ecosystem protection and suggest that protection efforts must be increased towards peninsular intermediate reefs to promote metapopulation resilience from natural and anthropogenic factors. [ABSTRACT FROM AUTHOR]

Se presenta dos tipos de anomalías pigmentarias en individuos de la focha andina Fulica ardesiaca (Rallidae), que habita el lago San Pablo del cantón Otavalo, provincia de Imbabura, Ecuador. Algunos individuos adultos presentan varias condiciones de despigmentación en el plumaje, que se pueden clasificar como leucismo parcial y envejecimiento progresivo. El primero ocurre por la falta de melanina y es de carácter hereditario, mientras que el segundo es la pérdida progresiva de pigmento y puede o no ser hereditario. En Ecuador este es el primer caso de estas anomalías pigmentarias en una misma metapoblación.

As a landscape becomes increasingly fragmented through habitat loss, the individual patches become smaller and more isolated and thus less likely to sustain a local population. Metapopulation theory is appropriate for analyzing fragmented landscapes because it combines empirical landscape features with species‐specific information to produce direct information on population extinction risks. This approach contrasts with descriptions of habitat fragments, which provide only indirect information on risk. Combining a spatially explicit metapopulation model with empirical data on endemic species' ranges and maps of habitat cover, we calculated the metapopulation capacity—a measure of a landscape's ability to sustain a metapopulation. Mangroves provide an ideal model landscape because they are of conservation concern and their patch boundaries are easily delineated. For 2000–20015, we calculated global metapopulation capacity for 99 metapopulations of 32 different bird species endemic to mangroves. Northern Australia and Southeast Asia had the highest richness of mangrove endemic birds. The Caribbean, Pacific coast of Central America, Madagascar, Borneo, and isolated patches in Southeast Asia in Myanmar and Malaysia had the highest metapopulation losses. Regions with the highest loss of habitat area were not necessarily those with the highest loss of metapopulation capacity. Often, it was not a matter of how much, but how the habitat was lost. Our method can be used by managers to evaluate and prioritize a landscape for metapopulation persistence. Article impact statement: Application of metapopulation theory shows where area of habitat loss is highest; metapopulation capacity is not necessarily also the highest. [ABSTRACT FROM AUTHOR]

Dada una metapoblación, que como tal, se encuentra distribuida en fragmentos o parches, podemos pensar que esta está en riesgo de extinción si la cantidad de parches ocupados está disminuyendo. En este sentido, una medida de conservación a considerar podría ser la incorporación de individuos a parches desocupados. Este proceso es conocido como conservación ex situ. En el presente trabajo supondremos una metapoblación extinguiéndose, cuya dinámica será modelada matemáticamente a través del modelo planteado por Richard Levins en su trabajo “Some demographic and genetic consequences of environmental heterogeneity for biological control”. Se incorporará al modelo el efecto de una medida de conservación ex situ, consistente en la colonización artificial de parches desocupados, con el propósito de evitar que la población total se extinga. La incorporación de esta medida de conservación será expresada a través de un sistema de ecuaciones diferenciales impulsivo, a partir del cual se generarán una serie de simulaciones, en orden a entender la dinámica a largo plazo y determinar qué factores influyen en el éxito de la medida de conservación.

Despite of the substantial economic and human health problems produced by rodents of the genus Rattus almost nothing is known about its actual dispersal. In the present study we analyze the genetic subdivision of R. norvegicus inhabiting poultry farms of Buenos Aires, Argentina, and the relation between geographic and genetic distances by means of variation in microsatellite loci. We genotyped 40 rats captured between April-06 and June-07 from nine poultry farms distributed in an area of 110 km². No genetic subdivision was found among different poultry farms. This result supports the hypothesis of high connectivity between R. norvegicus inhabiting poultry farms in Buenos Aires. Because this species is a known host of diverse zoonosis as leptospirosis and trichinosis, our results point out that there is a great risk of transmission for distances lower than 12 km. Health control and preventive measures should therefore be applied simultaneously in all nearby poultry farms. [ABSTRACT FROM AUTHOR]

Despite the broad environmental tolerance of the Military Macaw (Ara militaris) reflected in its wide ecological distribution, most surveyed populations in the few studied breeding areas in Mexico present, 100 individuals. Although records of the species include several regions across the country, most groups recorded include, 50 macaws. Prior to this report, the largest known breeding Mexican population documented was the Tehuaca´n-Cuicatla´n nesting colony with 100 macaws. Over the last 8 years, we surveyed the macaw population nesting in tropical coastal forests located in the southern portions of Bahia de Banderas, the bay where Puerto Vallarta in Jalisco is located. We systematically assessed the macaw population by counting the flocks occurring in 3 forested areas located 20–37 km apart and assumed to harbor different and independent macaw groups. The macaw abundance was surveyed during 35 consecutive months from February 2012 through December 2014. Based on location of the surveys, the timing of the observations, and the flight direction of the 3 distinct macaw groups, we inferred that each uses different foraging, roosting, and nesting areas. Higher abundance for each population was observed during February–May each year, contrasting with a low level of activity observed during the summer months of July–August. We assumed that the macaws exhibit nomadic behavior outside the region during summer. The 3 populations may constitute a metapopulation that congregates after the fledglings acquire flying skills during the initial months of the nonbreeding season on the 3 different areas. During March 2013, the highest concentration was registered in the Yelapa region, where 215 macaws were observed in a colonial roost, constituting the largest aggregation documented for the species. If data from the 3 populations surveyed are combined, the estimated number of macaws is 363 birds for 2014. Based on our data, we believe the region harbors a vital population for the long-term survival of the Military Macaw in central western Pacific and Mexico. [ABSTRACT FROM AUTHOR]

La Mancha Húmeda combines a surface, density and diversity of wetlands unique in the Iberian Peninsula, so as abundant and diverse waterfowl. Despite degradation and/or threats to wetlands and populations, management is concentrated in a few sites. Our hypothesis is that it is the complex, and not individual wetlands, which attracts and maintains this biodiversity. To contrast it, Levins' model of metapopulations is applied to 10 species of different functional groups and 10 representative wetlands along four hydrological cycles, one of them very humid. When analyzing the variation in the counts of birds, colonization and extinction rates, proportion of occupied habitats and habitat availability, it was observed that: 1. The method has been validated against the dynamics of wintering and summer populations. 2. Some species show a classical metapopulation strategy in the study period. 3. Loss of habitats may mean a high risk of decline in the populations of some species. It is concluded that the survival of many species depends on the maintenance of the asynchronous functioning of the wetlands, for which management at the wetland network level is necessary.\ [ABSTRACT FROM AUTHOR]

El río Negro alberga una metapoblación de la náyade Margaritifera margaritifera L. 1758 que no es demográficamente funcional. Su estructura poblacional está desequilibrada hacia tallas muy grandes y no se han detectado juveniles en más de una década de estudio. En el río existen graves problemas de conservación derivados del aterramiento, extensibles a la trucha Salmo trutta L. 1758, único hospedador de sus larvas. Entre 2002 y 2009 sucedieron de forma consecutiva graves riadas y la mayor sequía registrada en la cuenca. La mayor avenida en 100 años del año 2006 produjo el movimiento de gran parte de la población de náyades, con un impacto mortal que según tramos afectó entre el 5 y el 34% de los efectivos. Se comprobó una mortandad diferencial en relación con la topografía local y composición granulométrica del lecho, pero independiente de la densidad y la talla de los individuos. La sequía afectó al tercio final del cauce y supuso la pérdida del 37% de ejemplares del tramo. La aplicación de modelos poblacionales permite estimar que estos eventos estocásticos agravan significativamente el proceso de extinción, anticipando el presumible colapso demográfico teóricamente esperable para 2027-2032, provocado por la actuación continuada del resto de problemas. La aplicación de un plan de restauración del cauce, enfocado a las náyades y sus hospedadores, así como el rescate de adultos tras los eventos extremos, su asentamiento temporal en zonas favorables y la propagación de la especie sobre alevines de trucha son medidas urgentes que deberían desarrollarse antes de poder afrontar un programa de cría en cautividad que evite la extinción de la especie en la Cuenca del Duero.

Designing connected landscapes is among the most widespread strategies for achieving biodiversity conservation targets. The challenge lies in simultaneously satisfying the connectivity needs of multiple species at multiple spatial scales under uncertain climate and land-use change. To evaluate the contribution of remnant habitat fragments to the connectivity of regional habitat networks, we developed a method to integrate uncertainty in climate and land-use change projections with the latest developments in network-connectivity research and spatial, multipurpose conservation prioritization. We used land-use change simulations to explore robustness of species' habitat networks to alternative development scenarios. We applied our method to 14 vertebrate focal species of periurban Montreal, Canada. Accounting for connectivity in spatial prioritization strongly modified conservation priorities and the modified priorities were robust to uncertain climate change. Setting conservation priorities based on habitat quality and connectivity maintained a large proportion of the region's connectivity, despite anticipated habitat loss due to climate and land-use change. The application of connectivity criteria alongside habitat-quality criteria for protected-area design was efficient with respect to the amount of area that needs protection and did not necessarily amplify trade-offs among conservation criteria. Our approach and results are being applied in and around Montreal and are well suited to the design of ecological networks and green infrastructure for the conservation of biodiversity and ecosystem services in other regions, in particular regions around large cities, where connectivity is critically low. [ABSTRACT FROM AUTHOR]

Two types of pigmentary abnormalities in the Andean Coot Fulica ardesiaca (Rallidae) living in the San Pablo Lagoon, Imbabura-Ecuador, are presented. Several adult individuals show a variety of feather depigmentation patterns, which may be classified as partial leucism and progressive graying due to age. Whereas the first one is caused by lack of melanin and is hereditary, the second one is a progressive loss of pigment and is not necessarily hereditary. This is the first case of such pigmentary abnormalities within one meta-population in Ecuador. [ABSTRACT FROM AUTHOR]

El archipiélago de Juan Fernández y el de las islas Desventuradas, corresponden a dos pequenos grupos de islas oceánicas, separadas entre sí 460 mn y ubicadas aproximadamente a 360 mn frente a la costa chilena. La economía local de estas islas se basa casi exclusivamente en la extracción y comercialización de recursos marinos, focalizados principalmente en la explotación de la langosta (Jasusfrontalis). Esta especie endémica se encuentra distribuída en ambos archipiélagos conformando una metapoblación, donde su dinámica y estructura poblacional sería modulada por forzantes oceanográficos, especialmente durante su prolongada fase larval planctónica. Se evaluó la estructura poblacional y el grado de conectividad-retención dentro y entre las diferentes islas mediante el uso de modelos biofísicos acoplados (modelos hidrodinámicos provenientes del modelo OFES y un modelo individuo basado de J. frontalis). El análisis de los resultados del modelo hidrodinámico indica la presencia de estructuras de mesoescala asociadas al sistema de islas. Índices provenientes del modelo biofísico muestran niveles importantes de conectividad-retención dentro y entre los sistemas de islas y una fuerte variación interanual de estos. Los resultados de la modelación biofísica indican que la varibilidad en el reclutamiento asociado al archipiélago de Juan Fernández depende mayoritariamente de larvas originadas en este mismo sistema, con un aporte importante de reclutas hacia el archipiélago de las Desventuradas. Se realizaron estudios de sensibilidad del modelo biofísico para identificar forzantes potenciales de las variables dependientes del modelo (e.g. índices de conectividad-retención), resultando en que los patrones temporales y espaciales reproductivos, la duración del estadio larval y la temporada (ano) son altamente significativos. Finalmente, se propone que J. frontalis presenta una estructura metapoblacional con un alto nivel de conectividad en el archipiélago de Juan Fernández y un fuerte aporte de larvas hacia las islas Desventuradas. Estos flujos se ven determinados principalmente por el acoplamiento entre los factores biológicos y los factores oceanográficos imperantes.Located approximately 360 nm off the coast of Chile there is a disjoint realm of two small oceanic islands systems, the Juan Fernández and the Desventuradas archipelago. Currently the local economy of the islands is almost exclusively supported by the harvest and trade of marine resources, focusing mainly on the exploitation of the rock lobster (Jasus frontalis). This endemic species is distributed in both archipelagos, forming a metapopulation, whose population structure and dynamic is modulated by oceanographic forcing, especially during its extended planktonic larval phase. The population structure and the conection-retention within and between islands was assessed, based on the use of coupled biophysical model (the hidrodynamics model OFES and an individual-based model of J. frontalis). The analysis of the hydrodynamic model predictions showed the presence of mesoscale structures associated with the islands systems. The simulation results indicated significant levels of connectivity-retention within and between island systems showing also a strong interannual variation of these. Biophysical modeling results indicated that recruitment varibility associated with the Juan Fernández archipelago depends mainly on larvae originated within this system, which as well will contribute with recruits to the Desventuradas archipelago. The sensitivity analysis of the biophysical model to identify the potential biophysical forcing of the dependent variables of the model (e.g. connectivity-retention index), resulted in that temporal and spatial patterns reproductive larval stage duration and season (year) are highly significant factors. Finally, a metapopulation structure for J.frontalis, with a high level of connectivity in the archipelago of Juan Fernandez and a considerable amount of larvae in the Desventuradas islands is proposed. These fluxes are determined mainly by the coupling between prevailing biological and oceanographic factors.

Plant populations may experience local extinction and at the same time new populations may appear in nearby suitable locations. Species may also colonize the same site on multiple occasions. Here, we examined the impact of local extinction and recolonization on the genetic structure of wild populations of lima beans (Phaseolus lunatus) in the Central valley of Costa Rica. We compared genetic diversity from the samples taken from the populations before and after extinction at 13 locations using microsatellite markers. Locations were classified according to the occurrence of extinction episodes during the previous five years into three groups: 1) populations that experienced extinction for more than one year, and were later recolonized (recolonized), 2) populations that did not experience local extinction (control), and 3) populations that did not experience local extinction during the study, but were cut to experimentally simulate extinction (experimental). Our data did not show a clear tendency in variation in allele frequencies, expected heterozygosity, and effective number of alleles within and between groups of populations. However, we found that the level of genetic differentiation between samples collected at different times at the same location was different in the three groups of populations. Recolonized locations showed the highest level of genetic differentiation (mean Fst= 0.2769), followed by control locations (mean Fst= 0.0576) and experimental locations (mean Fst= 0.0189). Similar findings were observed for Nei’s genetic distance between samples (di,j= 0.1786, 0.0400, and 0.0037, respectively). Our results indicate that genetic change in lima beans depends on the duration and frequency of local extinction episodes. These findings also showed that control populations are not in equilibrium. Implications of these results for the establishment of conservation strategies of genetic resources of lima beans are discussed. Rev. Biol. Trop. 56 (3): 1023-1041. Epub 2008 September 30.Las poblaciones de plantas pueden experimentar extinción local, y al mismo tiempo, pueden surgir a sus alrededores nuevas poblaciones. Algunas especies pueden colonizar el mismo sitio en múltiples ocasiones. Aquí examinamos el impacto de la extinción local y recolonización en la estructura genética de poblaciones silvestres del frijol lima (Phaseolus lunatus) en el valle Central de Costa Rica. Comparamos la diversidad genética de muestras tomadas en poblaciones, antes y después de la extinción, en 13 sitios, usando marcadores de microsatélite. Según los episodios de extinción durante los cinco años previos, clasificamos los sitios así: 1) poblaciones que han experimentado extinción por más de un año, y después han recolonizado (recolonizado), 2) poblaciones que no han experimentado extinción local (control), y 3) poblaciones que no han experimentado extinción local durante el estudio, pero fueron cortadas experimentalmente, simulando una extinción (experimental). Nuestros datos no mostraron una clara tendencia en la variación de las frecuencias alélicas, heterozigosidad, o número efectivo de alelos en y entre grupos de poblaciones. Los niveles de diferenciación genética entre muestras recolectadas en diferentes momentos en el mismo sitio fueron diferentes en los tres grupos de poblaciones. Los sitios recolonizados mostraron el mayor nivel de diferenciación genética (Fst = 0.2769), seguidos de los sitios control (Fst= 0.0576) y sitios experimentales (Fst= 0.0189). Obtuvimos resultados similares en la distancia genética Neis entre muestras (d i,j = 0.1786, 0.0400, y 0.0037, respectivamente). Los cambios genéticos en los frijoles lima dependen de la duración y frecuencia de los episodios de extinción local. Las poblaciones "control" no están en equilibrio. Las implicaciones de estos resultados para el establecimiento de estrategias de conservación de los recursos genéticos de habas se encuentran en discusión.

Se utilizó la técnica de ADN Polimórfico Amplificado al Azar (RAPD) para analizar muestras de ADN de 70 individuos de C. acutus provenientes de los ríos Jesús María, Tárcoles y Tusubres en el Pacífico Central de Costa Rica para estimar la diversidad genética, la diferenciación entre poblaciones, el flujo genético y la distancia genética. La diversidad genética fue baja en los tres ríos H = 0.2201 en el río Jesús María, 0.2358 en el río Tárcoles y 0.2589 en el río Tusubres. La diversidad genética para el total de los individuos también fue baja, H = 0.2452. Entre las tres poblaciones hay una dinámica metapoblacional (G ST = 0.0367) principalmente en las poblaciones de los ríos Jesús María y Tárcoles. El valor de flujo genético (Nm = 13.1361) y el número de individuos registrado para cada río por Porras (2004) sugieren que la población del río Tárcoles está cumpliendo el papel de fuente y las de Jesús María y Tusubres constituyen los sumideros. Hubo relación directa entre la distancia genética y la distancia geográfica (z = 1.1449, r = 0.9731, p< 0.0010). Estos resultados indican la necesidad de diseñar una estrategia para la conservación de estos cocodrilos que considere la existencia de la metapoblación entre los tres ríos y también es importante realizar un estudio genético en el resto de la costa Pacífica del Costa Rica y en todo el ámbito de distribución de esta especie.The crocodylid Crocodylus acutus is found in the Central Pacific of Costa Rica only in small populations, and the species is protected by law. RAPD was used to analyze 70 DNA samples of Crocodylus acutus from the rivers Jesus Maria, Tarcoles and Tusubres in the Central Pacific of Costa Rica in order to estimate genetic diversity, differentiation among populations, gene flow and genetic distance between them. Genetic diversity was low in the three rivers, H = 0.2201 in the Jesus Maria river, 0.2358 in the Tarcoles river and 0.2589 in the Tusubres river. Among the three populations there is a metapopulational dynamic (GST = 0.0367), mainly between the populations of the Jesus Maria and Tarcoles rivers. The value of gene flow (Nm = 13.1361) and the number of individuals reported for each river in 2004 suggests that the population of the Tarcoles river is the source and those from Jesus Maria and Tusubres are the drains. There was a direct relationship between the genetic distance and the geographical distance (z =1.1449, r =0.9731, p< 0.0010). A conservation strategy for these crocodiles must consider the existence of the metapopulation between the three rivers and the importance of studying the genetics of the American Crocodile in the rest of the Pacific coast of Costa Rica, as well as over the entire distribution range of this species. Rev. Biol. Trop. 56 (3): 1471-1480. Epub 2008 September 30.

We examined the links between the science and policy of habitat corridors to better understand how corridors can be implemented effectively. As a case study, we focused on a suite of landscape-scale connectivity plans in tropical and subtropical Asia (Malaysia, Singapore, and Bhutan). The process of corridor designation may be more efficient if the scientific determination of optimal corridor locations and arrangement is synchronized in time with political buy-in and establishment of policies to create corridors. Land tenure and the intactness of existing habitat in the region are also important to consider because optimal connectivity strategies may be very different if there are few, versus many, political jurisdictions (including commercial and traditional land tenures) and intact versus degraded habitat between patches. Novel financing mechanisms for corridors include bed taxes, payments for ecosystem services, and strategic forest certifications. Gaps in knowledge of effective corridor design include an understanding of how corridors, particularly those managed by local communities, can be protected from degradation and unsustainable hunting. There is a critical need for quantitative, data-driven models that can be used to prioritize potential corridors or multicorridor networks based on their relative contributions to long-term metacommunity persistence. [ABSTRACT FROM AUTHOR]

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well-developed tools exist for prioritizing areas for one-time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost-effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost-effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost-effectiveness analysis. This allowed us to discern between cost-effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost-effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost-effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost-effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost-effective conservation under uncertainty. [ABSTRACT FROM AUTHOR]

The population structure of fishery resources and the impact of environmental factors over its productivity are important processes to be considered in fisheries management. Environmental factors could determine both, the success of larval drift as the population spatial structure and its changes of biomass. In this paper we show the environmental effect over distribution, abundance and spatial structure of nylon shrimp population (Heterocarpus reedi) off central Chile (25°-37°S) from trawling surveys carried out between 1996 and 2011. Environmental variables considered where sea surface concentration of chlorophyll-a and dissolved organic matter. Results show a geographical separation in population around 32°S. Shrimp density is higher in the southern zone, where concentration of chlorophyll-a and dissolved organic matter are high due to presence of river tributaries and coastal upwelling zones. In this area, the bulk of the adult population is concentrated, which could act as "source" population and thereby its influence on larval drift could explain both, the preponderance of juveniles in the northern area as the smallest size of its population ("pseudo-sink" population). In the southern area, a process of spatial and bathymetric expansion had driven the increase in population size over time, where the colonization and individual somatic growth had been the main mechanisms. We found that periods of good environmental conditions explain high densities of shrimp with a delay of two years, which might be related mainly with larval survival and enhanced recruitment and somatic growth. The aim of this study was to understand the spatial-temporal variability of the nylon shrimp density in the study area. [ABSTRACT FROM AUTHOR]

Habitat loss is the principal threat to species. How much habitat remains-and how quickly it is shrinking-are implicitly included in the way the International Union for Conservation of Nature determines a species' risk of extinction. Many endangered species have habitats that are also fragmented to different extents. Thus, ideally, fragmentation should be quantified in a standard way in risk assessments. Although mapping fragmentation from satellite imagery is easy, efficient techniques for relating maps of remaining habitat to extinction risk are few. Purely spatial metrics from landscape ecology are hard to interpret and do not address extinction directly. Spatially explicit metapopulation models link fragmentation to extinction risk, but standard models work only at small scales. Counterintuitively, these models predict that a species in a large, contiguous habitat will fare worse than one in 2 tiny patches. This occurs because although the species in the large, contiguous habitat has a low probability of extinction, recolonization cannot occur if there are no other patches to provide colonists for a rescue effect. For 4 ecologically comparable bird species of the North Central American highland forests, we devised metapopulation models with area-weighted self-colonization terms; this reflected repopulation of a patch from a remnant of individuals that survived an adverse event. Use of this term gives extra weight to a patch in its own rescue effect. Species assigned least risk status were comparable in long-term extinction risk with those ranked as threatened. This finding suggests that fragmentation has had a substantial negative effect on them that is not accounted for in their Red List category. Estimación del Riesgo de Extinción Mediante Modelos Metapoblacionales de Fragmentación a Gran Escala [ABSTRACT FROM AUTHOR]

Biogeographic theory predicts that rare species occur more often in larger, less-isolated habitat patches and suggests that patch size and connectivity are positive predictors of patch quality for conservation. However, in areas substantially modified by humans, rare species may be relegated to the most isolated patches. We used data from plant surveys of 81 meadow patches in the Georgia Basin of Canada and the United States to show that presence of threatened and endangered plants was positively predicted for patches that were isolated on small islands surrounded by ocean and for patches that were isolated by surrounding forest. Neither patch size nor connectivity were positive predictors of rare species occurrence. Thus, in our study area, human influence, presumably due to disturbance or introduction of competitive non-native species, appears to have overwhelmed classical predictors of rare species distribution, such that greater patch isolation appeared to favor presence of rare species. We suggest conservation planners consider the potential advantages of protecting geographically isolated patches in human-modified landscapes because such patches may represent the only habitats in which rare species are likely to persist. Influencia Humana y Predictores Biogeográficos Clásicos de la Ocurrencia de Especies Raras [ABSTRACT FROM AUTHOR]

Located approximately 360 nm off the coast of Chile there is a disjoint realm of two small oceanic islands systems, the Juan Fernández and the Desventuradas archipelago. Currently the local economy of the islands is almost exclusively supported by the harvest and trade of marine resources, focusing mainly on the exploitation of the rock lobster (Jasus frontalis). This endemic species is distributed in both archipelagos, forming a metapopulation, whose population structure and dynamic is modulated by oceanographic forcing, especially during its extended planktonic larval phase. The population structure and the conection-retention within and between islands was assessed, based on the use of coupled biophysical model (the hidrodynamics model OFES and an individual-based model of J. frontalis). The analysis of the hydrodynamic model predictions showed the presence of mesoscale structures associated with the islands systems. The simulation results indicated significant levels of connectivity-retention within and between island systems showing also a strong interannual variation of these. Biophysical modeling results indicated that recruitment varibility associated with the Juan Fernández archipelago depends mainly on larvae originated within this system, which as well will contribute with recruits to the Desventuradas archipelago. The sensitivity analysis of the biophysical model to identify the potential biophysical forcing of the dependent variables of the model (e.g. connectivity-retention index), resulted in that temporal and spatial patterns reproductive larval stage duration and season (year) are highly significant factors. Finally, a metapopulation structure for J. frontalis, with a high level of connectivity in the archipelago of Juan Fernandez and a considerable amount of larvae in the Desventuradas islands is proposed. These fluxes are determined mainly by the coupling between prevailing biological and oceanographic factors. [ABSTRACT FROM AUTHOR]

Effective population size (N) determines the strength of genetic drift in a population and has long been recognized as an important parameter for evaluating conservation status and threats to genetic health of populations. Specifically, an estimate of N is crucial to management because it integrates genetic effects with the life history of the species, allowing for predictions of a population's current and future viability. Nevertheless, compared with ecological and demographic parameters, N has had limited influence on species management, beyond its application in very small populations. Recent developments have substantially improved N estimation; however, some obstacles remain for the practical application of N estimates. For example, the need to define the spatial and temporal scale of measurement makes the concept complex and sometimes difficult to interpret. We reviewed approaches to estimation of N over both long-term and contemporary time frames, clarifying their interpretations with respect to local populations and the global metapopulation. We describe multiple experimental factors affecting robustness of contemporary N estimates and suggest that different sampling designs can be combined to compare largely independent measures of N for improved confidence in the result. Large populations with moderate gene flow pose the greatest challenges to robust estimation of contemporary N and require careful consideration of sampling and analysis to minimize estimator bias. We emphasize the practical utility of estimating N by highlighting its relevance to the adaptive potential of a population and describing applications in management of marine populations, where the focus is not always on critically endangered populations. Two cases discussed include the mechanisms generating N estimates many orders of magnitude lower than census N in harvested marine fishes and the predicted reduction in N from hatchery-based population supplementation. [ABSTRACT FROM AUTHOR]

Sahelian Africa makes up the native range of pearl millet and the impact of domestication on the genetic diversity of wild, intermediate, and cultivated subspecies is still poorly understood. Wild populations are known to spontaneously germinate throughout this range and hybridize with cultivated material. To investigate genetic structure, populations of pearl millet from several African countries were analyzed at the morphological and molecular levels for diversity. Results demonstrate how little differentiation there is between subspecies and populations. It appears that pearl millet throughout the Sahel remains a metapopulation with large hybrid zones. These results have important implications for conservation of pearl millet. [ABSTRACT FROM AUTHOR]

Human-induced habitat fragmentation constitutes a major threat to biodiversity. Both genetic and demographic factors combine to drive small and isolated populations into extinction vortices. Nevertheless, the deleterious effects of inbreeding and drift load may depend on population structure, migration patterns, and mating systems and are difficult to predict in the absence of crossing experiments. We performed stochastic individual-based simulations aimed at predicting the effects of deleterious mutations on population fitness (offspring viability and median time to extinction) under a variety of settings (landscape configurations, migration models, and mating systems) on the basis of easy-to-collect demographic and genetic information. Pooling all simulations, a large part (70%) of variance in offspring viability was explained by a combination of genetic structure (FST ) and within-deme heterozygosity (HS ). A similar part of variance in median time to extinction was explained by a combination of local population size (N ) and heterozygosity (HS ). In both cases the predictive power increased above 80% when information on mating systems was available. These results provide robust predictive models to evaluate the viability prospects of fragmented populations. [ABSTRACT FROM AUTHOR]

Population viability analysis (PVA) is an effective framework for modeling species- and habitat-recovery efforts, but uncertainty in parameter estimates and model structure can lead to unreliable predictions. Integrating complex and often uncertain information into spatial PVA models requires that comprehensive sensitivity analyses be applied to explore the influence of spatial and nonspatial parameters on model predictions. We reviewed 87 analyses of spatial demographic PVA models of plants and animals to identify common approaches to sensitivity analysis in recent publications. In contrast to best practices recommended in the broader modeling community, sensitivity analyses of spatial PVAs were typically ad hoc, inconsistent, and difficult to compare. Most studies applied local approaches to sensitivity analyses, but few varied multiple parameters simultaneously. A lack of standards for sensitivity analysis and reporting in spatial PVAs has the potential to compromise the ability to learn collectively from PVA results, accurately interpret results in cases where model relationships include nonlinearities and interactions, prioritize monitoring and management actions, and ensure conservation-planning decisions are robust to uncertainties in spatial and nonspatial parameters. Our review underscores the need to develop tools for global sensitivity analysis and apply these to spatial PVA. [ABSTRACT FROM AUTHOR]

Studies on riparian buffers have usually focused on the amount of land needed as habitat for the terrestrial life stages of semiaquatic species. Nevertheless, the landscape surrounding wetlands is also important for other key processes, such as dispersal and the dynamics of metapopulations. Multiple elements that influence these processes should therefore be considered in the delineation of buffers. We analyzed landscape elements (forest cover, density of roads, and hydrographic network) in concentric buffers to evaluate the scale at which they influence stream amphibians in 77 distinct landscapes. To evaluate whether our results could be generalized to other contexts, we determined whether they were consistent across the study areas. Amphibians required buffers of 100–400 m of suitable terrestrial habitat, but interspecific differences in the amount of habitat were large. The presence of amphibians was related to roads and the hydrographic network at larger spatial scales (300–1500 m), which suggests that wider buffers are needed with these elements. This pattern probably arose because these elements influence dispersal and metapopulation persistence, processes that occur at large spatial scales. Furthermore, in some cases, analyses performed on different sets of landscapes provided different results, which suggests caution should be used when conservation recommendations are applied to disparate areas. Establishment of riparian buffers should not be focused only on riparian habitat, but should take a landscape perspective because semiaquatic species use multiple elements for different functions. This approach can be complex because different landscape elements require different spatial extents. Nevertheless, a shift of attention toward the management of different elements at multiple spatial scales is necessary for the long-term persistence of populations. [ABSTRACT FROM AUTHOR]

The crocodylid Crocodylus acutus is found in the Central Pacific of Costa Rica only in small populations, and the species is protected by law. RAPD was used to analyze 70 DNA samples of Crocodylus acutus from the rivers Jesus Maria, Tarcoles and Tusubres in the Central Pacific of Costa Rica in order to estimate genetic diversity, differentiation among populations, gene flow and genetic distance between them. Genetic diversity was low in the three rivers, H = 0.2201 in the Jesus Maria river, 0.2358 in the Tarcoles river and 0.2589 in the Tusubres river. Among the three populations there is a metapopulational dynamic (GST = 0.0367), mainly between the populations of the Jesus Maria and Tarcoles rivers. The value of gene flow (Nm = 13.1361) and the number of individuals reported for each river in 2004 suggests that the population of the Tarcoles river is the source and those from Jesus Maria and Tusubres are the drains. There was a direct relationship between the genetic distance and the geographical distance (z =1.1449, r =0.9731, p< 0.0010). A conservation strategy for these crocodiles must consider the existence of the metapopulation between the three rivers and the importance of studying the genetics of the American Crocodile in the rest of the Pacific coast of Costa Rica, as well as over the entire distribution range of this species. [ABSTRACT FROM AUTHOR]

Plant populations may experience local extinction and at the same time new populations may appear in nearby suitable locations. Species may also colonize the same site on multiple occasions. Here, we examined the impact of local extinction and recolonization on the genetic structure of wild populations of lima beans (Phaseolus lunatus) in the Central Valley of Costa Rica. We compared genetic diversity from the samples taken from the populations before and after extinction at 13 locations using microsatellite markers. Locations were classified according to the occurrence of extinction episodes during the previous five years into three groups: 1) populations that experienced extinction for more than one year, and were later recolonized (recolonized), 2) populations that did not experience local extinction (control), and 3) populations that did not experience local extinction during the study, but were cut to experimentally simulate extinction (experimental). Our data did not show a clear tendency in variation in allele frequencies, expected heterozygosity, and effective number of alleles within and between groups of populations. However, we found that the level of genetic differentiation between samples collected at different times at the same location was different in the three groups of populations. Recolonized locations showed the highest level of genetic differentiation (meanFst = 0.2769), followed by control locations (meanFst = 0.0576) and experimental locations (meanFst = 0.0189). Similar findings were observed for Nei's genetic distance between samples (di,j = 0.1786, 0.0400, and 0.0037, respectively). Our results indicate that genetic change in lima beans depends on the duration and frequency of local extinction episodes. These findings also showed that control populations are not in equilibrium. Implications of these results for the establishment of conservation strategies of genetic resources of lima beans are discussed. [ABSTRACT FROM AUTHOR]

Under the U.S. Endangered Species Act (ESA), a species can be listed if it is at risk “in all or a significant portion of its range,” but the ESA provides no guidance on how to interpret this key phrase. We propose a simple test to determine whether the areas of a species' range in which it is currently at risk amount to a significant portion: If the species were to become extirpated from these areas, at that point would the entire species be at risk? If so, then these areas represent a significant portion of the species' range. By establishing the species itself as the point of reference for determining significance, this test directs attention to biological risk factors and avoids difficulties inherent in subjective evaluations of importance to humans. For broadly distributed species this framework could provide ESA protection due to cumulative risks before the entire species met the criteria to be considered threatened or endangered. This framework also allows a somewhat broader concept of range to include major components of diversity necessary for long-term persistence. The concept of a historical template (i.e., conditions under which the species was known to be viable) is important in providing a fixed reference point for evaluating viability. Empirical examples illustrate how these concepts have been applied in recent ESA listing determinations. Most ESA-listed units of Pacific salmon (Oncorhynchus spp.) can be divided into multiple strata that differ in terms of ecology, geology, or life-history traits of the component populations. The goal of ESA recovery planning is to restore viable populations in enough strata that the listed unit as a whole is no longer threatened or endangered in all or a significant portion of its range. In a recent review of Pacific herring (Clupea pallasii ) in Puget Sound, current status (some populations increasing and others declining) was evaluated in the context of the historical template, and it was concluded that current patterns of distribution and abundance do not depart substantially from what would be expected at any point in time under natural conditions in a large metapopulation. The Canadian lynx (Lynx canadensis ) is ESA listed in the contiguous United States, where it occurs in four geographic areas. Populations in one region, the Northern Rockies/Cascades, have always been the most important for long-term persistence of the species in the United States. Because the other regions never contained more than limited amounts of good-quality lynx habitat, those areas are not considered to represent a significant portion of the species' range. [ABSTRACT FROM AUTHOR]

Pool-breeding amphibian populations operate at multiple scales, from the individual pool to surrounding upland habitat to clusters of pools. When metapopulation dynamics play a role in long-term viability, conservation efforts limited to the protection of individual pools or even pools with associated upland habitat may be ineffective over the long term if connectivity among pools is not maintained. Connectivity becomes especially important and difficult to assess in regions where suburban sprawl is rapidly increasing land development, road density, and traffic rates. We developed a model of connectivity among vernal pools for the four ambystomatid salamanders that occur in Massachusetts and applied it to the nearly 30,000 potential ephemeral wetlands across the state. The model was based on a modification of the kernel estimator (a density estimator commonly used in home range studies) that takes landscape resistance into account. The model was parameterized with empirical migration distances for spotted salamanders (Ambystoma maculatum ), dispersal distances for marbled salamanders (A. opacum ), and expert-derived estimates of landscape resistance. The model ranked vernal pools in Massachusetts by local, neighborhood, and regional connectivity and by an integrated measure of connectivity, both statewide and within ecoregions. The most functionally connected pool complexes occurred in southeastern and northeastern Massachusetts, areas with rapidly increasing suburban development. In a sensitivity analysis estimates of pool connectivity were relatively insensitive to uncertainty in parameter estimates, especially at the local and neighborhood scales. Our connectivity model could be used to prioritize conservation efforts for vernal-pool amphibian populations at broader scales than traditional pool-based approaches. [ABSTRACT FROM AUTHOR]

The actual relation surface-perimeter of Torotoro National Park (Potosi, Bolivia) was analyzed, and on its basis, minimal required surface's indexes were calculated for Puma concolor, Oreailurus jacobita and Lycalopex culpaeus populations. Data obtained were compared to the current effective conservation surface (47% of the total surface) and showed a clear deficiency, because the minimum surface required to conserve minimal viable populations of these carnivores is 105 times the Park's protected surface (166 km2) for P. concolor, 273 times for O. jacobita and 5 times for L. Culpaeus. [ABSTRACT FROM AUTHOR]

The Mexican prairie dog lives in a small (500-600 km2) area of northeastern Mexico. The species is listed as endangered due to habitat fragmentation from recent large-scale agricultural development in the northern part of its limited geographical range and from shrub encroachment in the south. In this work we aim to study the role of Mexican prairie dog in the ecology of grasslands in the southern Chihuahuan Desert. Most of the species' colonies, particularly in the far south of its range, occur today in short grasslands that grow on low productivity, gypsum-derived soils where the rate of such shrub encroachment is reduced. A survey of the region surrounding these southern colonies indicated that this has not always been the case as evidence of the species' occurrence on more productive alluvial soils in the past is apparent. Biomass production and seasonal prairie dog densities were measured on these low productivity soils in the south of its range and on richer and deeper alluvial soils to the north. Total biomass production was seven times greater and densities were three-and-one-half times greater on the deeper alluvial soils. Adult seasonal densities were not significantly different within a soil type during the period monitored while juvenile densities increased significantly in the summer censuses due to the birth of young. The similar seasonal densities at each site suggest that the Mexican prairie dog is resource limited. An inferential study of the development of one isolated colony on the more productive alluvial soils in the north of the species' range showed lower prairie dog densities in the center of the colony and at the edge of the colony in the zone of recent expansion than in the area peripheral to the center. Vegetation coverage was too scarce in the center of the colony to quantify. The areas peripheral to the center and in the zone of expansion were reduced in coverage of grasses and sedges in comparison to the unutilized surrounding grassland while the palatable grass, Bouteloua gracilis, was absent in the center and periphery of the colony and increased significantly in coverage from the zone of expansion to the adjoining grassland. Such low productivity grasslands may have served as refuges for the species during previous episodes of shrub encroachment in the Holocene. In addition, the natural fragmentation of such grasslands suggested that the Mexican prairie dog might function as a metapopulation. Colonizations and extinctions were recorded at monitored areas on each soil type. The major difference between the two complexes was due to the greater productivity of the alluvial soils in the north. Consequently, three times as many young per hectare are produced on these soils, greatly increasing the probability of the species maintaining an extant colony or successfully founding new colonies there. The probability of extinction of the Mexican prairie dog is higher in the south of its range due to these lower densities and conservation of the species there should involve the systematic transplantation of individuals from colonies on the richer alluvial soils to the north. [ABSTRACT FROM AUTHOR]

The importance of unprotected habitats for the persistence of species in reserve networks is likely to be high for species living in highly fragmented habitat in which regional persistence depends on metapopulation processes. The dingy skipper butterfly (Erynnis tages ) is a regionally rare declining species in Britain. In the Creuddyn Peninsula (North Wales), it inhabits patches of its host plant, Lotus corniculatus L., growing in lightly grazed areas in sheltered microhabitats, and its regional distribution is dominated by metapopulation processes. In this area, 16 (61%) out of 26.20 ha of dingy skipper habitat are located in reserves. The remaining unprotected habitat is mostly located in wasteland areas vulnerable to urban development. Using a metapopulation model, the incidence function model, I evaluated the extent to which the persistence of the dingy skipper in the landscape could be guaranteed with the existing reserve network. According to model projections, the dynamics within the reserve system were relatively stable when the unprotected habitat remained, with a maximum of 4% simulation replicates going extinct in a 100-year time frame. When unprotected habitat was completely removed, however, the dynamics in the reserve network became markedly unstable, with an increased extinction risk ranging from 15 to 36%. We calculated a relatively simple measure of “patch importance,” the colonization potential, for each patch. The incidence function model predicted that for low and medium levels of regional stochasticity (σ value from 0 to 0.2), protecting only a relatively small number (four to six) of large and well-connected patches (high colonization potential) in addition to the existing reserves would be enough to decrease notably the extinction risk of the dingy skipper metapopulation. The number of patches needed to be increased (11 patches) for high levels of regional stochasticity (σ= 0.3). My results suggest that long-term persistence of a regionally rare butterfly in a reserve network may depend on the presence of unprotected habitat. For a more realistic estimate of the efficiency of reserves for protecting rare species, conservation biologists should consider incorporating metapopulation dynamics in their evaluations of persistence in existing reserves. [ABSTRACT FROM AUTHOR]

The effects of climate change and habitat destruction and their interaction are likely to be the greatest challenge to animal and plant conservation in the twenty-first century. We used the world's smallest butterfly, the Sinai baton blue (Pseudophilotes sinaicus ), as an exemplar of how global warming and human population pressures may act together to cause species extinctions. We mapped the entire global range of this butterfly and obtained extensive data on the intensity of livestock grazing. As with an increasing number of species, it is confined to a network of small habitat patches and is threatened both by indirect human-induced factors (global warming) and by the direct activities of humans (in this case, livestock grazing and collection of medicinal plants). In the absence of global warming, grazing, and plant collection, our model suggested that the butterfly will persist for at least 200 years. Above a threshold intensity of global warming, the chance of extinction accelerated rapidly, implying that there may be an annual average temperature, specific to each endangered species, above which extinction becomes very much more likely. By contrast, there was no such threshold of grazing pressure—the chance of extinction increased steadily with increasing grazing. The impact of grazing, however, decreased with higher levels of year-to-year variation in habitat quality. The effect of global warming did not depend on the future level of grazing, suggesting that the impacts of global warming and grazing are additive. If the areas of habitat patches individually fall below certain prescribed levels, the butterfly is likely to go extinct. Two patches were very important for persistence: if either were lost the species would probably go extinct. Our results have implications for the conservation management of all species whose habitats are at risk because of the direct activities of humans and in the longer term because of climate change. [ABSTRACT FROM AUTHOR]

Aside from Kruger National Park, no other suitable reserves of sufficient size exist in South Africa that will hold a viable population of wild dogs (Lycaon pictus). Consequently, conservation efforts have been focused on creating a metapopulation through a series of wild dog reintroductions into isolated fenced reserves. Additional potential exists for conserving wild dogs on private ranch land. Establishing the metapopulation was an expensive process, accounting for approximately 75% of the US$380,000 spent on wild dog conservation in South Africa during 1997-2001. The principal goal of the metapopulation project was to reduce the risk of catastrophic population decline. Now that this has been achieved, we developed a uniform cost-efficiency index to estimate the cost efficiency of current and potential future conservation strategies in South Africa. Conserving wild dogs in large protected areas was predicted to be the most cost-efficient conservation strategy (449 packs/$100,000 expenditure). Establishing the metapopulation has been less cost efficient (23 packs/$100,000), and expansion of the metapopulation was predicted to be even less cost efficient if predation by wild dogs results in additional costs, as is to be expected if private reserves are used for reintroductions (3-13 packs/$100,000). Because of low logistical costs, conserving wild dogs in situ on private ranch land was potentially more cost efficient than reintroducing wild dogs (14-27 packs/$100,000). We recommend that donor funding be used to reintroduce wild dogs into transfrontier parks, when they are established, to maintain the existing metapopulation and to establish conservation programs involving wild dogs on private ranch land. Investing in the expansion of the metapopulation should be limited to state-owned nature reserves willing to carry predation costs without compensation. [ABSTRACT FROM AUTHOR]

We used a spatially explicit population model that was generalized to produce nine ecological profiles of long-lived species with stable home ranges and natal dispersal to investigate the effects of habitat loss and fragmentation on population dynamics. We simulated population dynamics in landscapes composed of three habitat types (good-quality habitat ranging from 10–25%, poor-quality habitat ranging from 10–70%, and matrix). Landscape structures varied from highly fragmented to completely contiguous. The specific aims of our model were (1) to investigate under which biological circumstances the traditional approach of using two types only (habitat and matrix) failed and assess the potential impact of restoring matrix to poor-quality habitat, (2) to investigate how much of the variation in population size was explained by landscape composition alone and which key attributes of landscape structure can serve as predictors of population response, and (3) to estimate the maximum fragmentation effects expressed in equivalent pure loss of good-quality habitat. Poor-quality habitat mattered most in situations when it was generally not considered (i.e., for metapopulations or spatially structured populations when it provides dispersal habitat). Population size increased up to 3 times after restoring matrix to poor-quality habitat. Overall, habitat amount accounted for 68% of the variation in population size, whereas ecological profile and fragmentation accounted for approximately 13% each. The maximal effect of (good-quality) habitat fragmentation was equivalent to a pure loss of up to 15% of good-quality habitat, and the maximal loss of individuals resulting from maximal fragmentation reached 80%. Abundant dispersal habitat and sufficiently large dispersal potential, however, resulted in functionally connected landscapes, and maximal fragmentation had no effect at all. Our findings suggest that predicting fragmentation effects requires a good understanding of the biology and habitat use of the species in question and that the uniqueness of species and the landscapes in which they live confound simple analysis. [ABSTRACT FROM AUTHOR]

To conserve biological diversity, protected-area networks must be based not only on current species distributions but also on the landscape's long-term capacity to support populations. We used spatially explicit population models requiring detailed habitat and demographic data to evaluate the ability of existing park systems in the Rocky Mountain region (U.S.A. and Canada) to sustain populations of mammalian carnivores. Predicted patterns of extirpation agreed with those from logistic-regression models based only on park size and connectedness (or isolation) for the grizzly bear ( ) in developed landscapes (northern U.S. Rocky Mountains) and semideveloped landscapes (southern Canadian Rocky Mountains). The area-isolation model performed poorly where the landscape matrix contained large amounts of suitable habitat (northern Canadian Rocky Mountains). Park area and connectedness were poor predictors of gray wolf (Canis lupus ) occurrence because of this species' broader-scale range dynamics and greater ability to inhabit the landscape matrix. A doubling of park area corresponded to a 47% and 57% increase in projected grizzly bear population persistence in developed and semideveloped landscapes, respectively. A doubling of a park's connectedness index corresponded to a 81% and 350% increase in population persistence in developed and semideveloped landscapes, respectively, suggesting that conservation planning to enhance connectivity may be most effective in the earliest stages of landscape degradation. The park area and connectivity required for population persistence increased as the landscape matrix became more hostile, implying that the relatively small combined area of parks in the boreal forest and other undeveloped regions may fall below the threshold for species persistence if parks become habitat islands. Loss of carnivores from boreal landscapes could further reduce the viability of temperate populations occupying refugia at the southern range margin. Spatially realistic population models may be more informative than simpler patch-matrix models in predicting the effects of landscape change on population viability across a continuum of landscape degradation. [ABSTRACT FROM AUTHOR]