Translocation is a non-lethal practice used to manage carnivore-livestock conflicts. Nevertheless, its use has been questioned due to its low success rate and high cost. We performed a literature review to assess the effectiveness of translocation, human-related mortality and cost. We estimated the overall effectiveness to be 42% 6 6, felids were involved in 70% of the translocations and 80% of the case studies were conducted in North America and Africa. Human-related mortality accounted for the 83% of deaths after translocations. Translocation cost per individual was estimated at US$ 3,756 6 357 (N ¼ 16), a sum equivalent to compensate for up to 30 livestock heads. For conservation purposes, translocation is costly and less effective than other alternatives such as compensation with best herding practices.

Anthropogenic habitat disturbance is a strong biodiversity change driver that compromises not only the species persistence but also the ecological interactions in which they are involved. Even though seed dispersal is a key interaction involved in the recruitment of many tree species and in consequence critical for biodiversity maintenance, studies assessing the effect of different anthropogenic disturbance drivers on this interaction have not been performed under a meta-analytical framework. We assessed the way habitat fragmentation and degradation processes affect species diversity (abundance and species richness) and interaction rates (i.e., fruit removal and visitation rates) of different groups of seed-disperser species at a global scale. We obtained 163 case studies from 37 articles. Results indicate that habitat degradation had a negative effect on seed-disperser animal diversity, whereas habitat fragmentation had a negative effect on interaction rates. Birds and insects were more sensitive in terms of their diversity, whereas mammals showed a negative effect on interaction rates. Regarding habitat, both fragmentation and degradation had a negative effect on seed-disperser animal diversity only in temperate habitats, and negative effects on interaction rates in tropical and temperate habitats. Our results indicate that the impact of human disturbance on seed-disperser species and interactions is not homogeneous. On the contrary, the magnitude of effects seems to be dependent on the type of disturbance, taxonomic group under assessment, and geographical region where the human impact occurs.

Dromiciops gliroides is an arboreal marsupial found in the temperate forests of South America (36-43 °S). This species is the sole extant representative of the order Microbiotheria, and is a key seed disperser of many native plant species, including the keystone mistletoe Tristerix corymbosus. Here, we synthesized the current knowledge on the ecological aspects of this species, and compared the available information from Argentina and Chile. Population density (23 ± 2 (mean ± SE) individual/ha) and home range (1.6 ± 0.6 ha) appear to be relatively similar across a marked ecological gradient in the mainland, but lower densities (7 ± 2 individual/ha) and smaller home ranges (0.26 ± 0.04 ha) were detected at island sites. We detected regional variation in body condition in Chile, but there were no significant differences across a wider E-W gradient. Movement patterns fit a random walk model; such behavior might have important consequences in shaping plant's spatial patterns. Although our data suggest that D. gliroides is more tolerant to habitat disturbance than previously thought, its incapability to disperse across non-forested areas suggests that the rapid rate of habitat loss and fragmentation that characterizes southern temperate forests likely poses a serious threat to this species. These ecological similarities are surprising given that forests studied receive dramatically different rainfall and correspond to distinct forest types. The evidence synthetized here dispels some of the myths about this species but also stresses the need for more comprehensive ecological studies across its distribution range.

2016-12-24T18:10:15

Genetic diversity is a key factor for population survival and evolution. However, anthropogenic habitat disturbance can erode it, making populations more prone to extinction. Aiming to assess the global effects of habitat disturbance on plant genetic variation, we conducted a meta-analysis based on 92 case studies obtained from published literature. We compared the effects of habitat fragmentation and degradation on plant allelic richness and gene diversity (equivalent to expected heterozygosity) and tested whether such changes are sensitive to different life-forms, life spans, mating systems, and commonness. Anthropogenic disturbance had a negative effect on allelic richness, but not on gene diversity. Habitat fragmentation had a negative effect on genetic variation, whereas habitat degradation had no effect. When we examined the individual effects in fragmented habitats, allelic richness and gene diversity decreased, but this decrease was strongly dependent on certain plant traits. Specifically, common long-lived trees and self-incompatible species were more susceptible to allelic richness loss. Conversely, gene diversity decreased in common short-lived species (herbs) with self-compatible reproduction. In a wider geographical context, tropical plant communities were more sensitive to allelic richness loss, whereas temperate plant communities were more sensitive to gene diversity loss. Our synthesis showed complex responses to habitat disturbance among plant species. In many cases, the absence of effects could be the result of the time elapsed since the disturbance event or reproductive systems favoring self-pollination, but attention must be paid to those plant species that are more susceptible to losing genetic diversity, and appropriate conservation should be actions taken. Meta-Análisis de los Efectos Diferenciales de la Fragmentación y Degradación del Hábitat sobre la Diversidad Genética de las PlantasResumen: La diversidad genética es un factor clave para la supervivencia y evolución de las poblaciones. Sin embargo, la perturbación antropogénica de los hábitats puede dañar esta diversidad, volviendo a las poblaciones más susceptibles a la extinción. Con el objetivo de evaluar los efectos globales de la perturbación del hábitat sobre la variación genética de las plantas, realizamos un meta-análisis basado en 92 estudios de caso obtenidos de la literatura publicada. Comparamos los efectos de la degradación y fragmentación del hábitat sobre la riqueza de alelos y la diversidad de genes (equivalente a la heterocigosidad esperada) de las plantas y probamos si dichos cambios son sensibles para diferentes formas de vida, tiempos de vida, sistemas de apareamiento y preponderancia. La perturbación antropogénica tuvo un efecto negativo sobre la riqueza de alelos, pero no sobre la diversidad genética. La fragmentación del hábitat tuvo un efecto negativo sobre la variación genética, mientras que la degradación del hábitat no tuvo efecto. Cuando examinamos los efectos individuales en los hábitats fragmentados, Article...

Abstract. Anthropogenic disturbance can modify habitat structure and resource availability, potentially disrupting ecological interactions. This issue may be critical for pollination and seed dispersal, which determine natural regeneration. The mistletoe Tristerix corymbosus is almost exclusively pollinated by a hummingbird (Sephanoides sephaniodes) and dispersed by a marsupial (Dromiciops gliroides). We examined the extent to which human-induced habitat change and resource availability influence the interaction rate of this plant-pollinator-seed disperser system, along a forest transformation gradient (from native forest to exotic plantations). We estimated visitation rates of S. sephaniodes and D. gliroides on 70 T. corymbosus mistletoes using camera traps. We related visitation rates to habitat structural features and resource availability (flowers and fruits of the mistletoe and the neighborhood) using spatially explicit models. Sephanoides sephaniodes and D. gliroides visitation rates responded positively to shrub and bamboo cover, moss abundance, and mistletoe spatial arrangement. Pollination and seed dispersal interactions were sensitive to the flower and fleshy-fruit neighborhoods, being variable across months. Further, D. gliroides showed a non-random spatial association with fleshy-fruited plants. A larger sunlight incidence on disturbed habitats may prevent the disruption of key ecological interactions by increasing resource availability. This effect would result from the presence of shade-intolerant plants, which are benefited by sunlight exposure. Patches of disturbed habitat may enhance landscape heterogeneity, providing complementary resources to the native remnants.

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Summary1. Transformed habitats are the result of deliberate replacement of native species by an exotic monoculture, involving changes in biotic and abiotic conditions. Despite the fact that transformed habitats are becoming more common and constitute a major biodiversity change driver, little is known about the scale-dependent responses of plant-animal mutualisms. 2. Aiming to test the multiscale responses of pollination and seed dispersal in a habitat transformation scenario, we examined a gradient of native and transformed habitats at three spatial scales (0-50, 50-100 and 100-250 m) and focused on a highly specialized mutualistic system composed of a hemiparasitic mistletoe (Tristerix corymbosus) that is almost exclusively pollinated by a hummingbird (Sephanoides sephaniodes) and dispersed by an arboreal marsupial (Dromiciops gliroides). 3. Even though mistletoes were found along the gradient, they were more abundant and more densely aggregated when the transformed habitat was dominant. Disperser and pollinator activity also increased as the transformed habitat becomes dominant, at the scale of 0-50 and 50-100 m, respectively. Furthermore, crop size and disperser activity covaried at broad and intermediate scales, whereas recruitment covaried at intermediate and fine scales. Moreover, disperser activity and the number of seedlings were spatially associated, stressing D. gliroides' role in the recruitment of the mistletoe. 4. Synthesis. This highly specialized mutualistic system seems to be responding positively to the habitat structure modifications associated with Eucalyptus plantations. However, the actual costs (e.g. reduced gene flow, increased herbivory) in these transformed habitats are yet to be assessed.