Luz A., Guèze M., Paneque-Gálvez J., Pino J., MacIá M., Orta-Martínez M., Reyes-Garciá V. (2015) How Does Cultural Change Affect Indigenous Peoples' Hunting Activity? An Empirical Study among the Tsimane' in the Bolivian Amazon. Conservation and Society. 13: 382-394.LinkDoi: 10.4103/0972-4923.179879
Wildlife hunting is an important economic activity that contributes to the subsistence of indigenous peoples and the maintenance of their cultural identity. Changes in indigenous peoples' ways of life affect the way they manage the ecosystems and resources around them, including wildlife populations. This paper explores the relationship between cultural change, or detachment from traditional culture, and hunting behaviour among the Tsimane', an indigenous group in the Bolivian Amazon. We interviewed 344 hunters in 39 villages to estimate their hunting activity and the degree of cultural change among them. We used multilevel analyses to assess the relationships between three different proxies for cultural change at the individual level (schooling, visits to a market town, and detachment from tradition), and the following two independent variables: 1) probability of engaging in hunting (i.e., hunting activity) and 2) hunting efficiency with catch per unit effort (CPUE). We found a statistically significant negative association between schooling and hunting activity. Hunting efficiency (CPUE biomass/km) was positively associated with visits to a market town, when holding other co-variates in the model constant. Other than biophysical factors, such as game abundance, hunting is also conditioned by social factors (e.g., schooling) that shape the hunters' cultural system and impel them to engage in hunting or deter them from doing so. © 2015 Luz et al.
Maas B., Karp D.S., Bumrungsri S., Darras K., Gonthier D., Huang J.C.-C., Lindell C.A., Maine J.J., Mestre L., Michel N.L., Morrison E.B., Perfecto I., Philpott S.M., Sekercioglu C.H., Silva R.M., Taylor P.J., Tscharntke T., Van Bael S.A., Whelan C.J., Williams-Guillen K. (2015) Bird and bat predation services in tropical forests and agroforestry landscapes. Biological Reviews. : 0-0.LinkDoi: 10.1111/brv.12211
Understanding distribution patterns and multitrophic interactions is critical for managing bat- and bird-mediated ecosystem services such as the suppression of pest and non-pest arthropods. Despite the ecological and economic importance of bats and birds in tropical forests, agroforestry systems, and agricultural systems mixed with natural forest, a systematic review of their impact is still missing. A growing number of bird and bat exclosure experiments has improved our knowledge allowing new conclusions regarding their roles in food webs and associated ecosystem services. Here, we review the distribution patterns of insectivorous birds and bats, their local and landscape drivers, and their effects on trophic cascades in tropical ecosystems. We report that for birds but not bats community composition and relative importance of functional groups changes conspicuously from forests to habitats including both agricultural areas and forests, here termed 'forest-agri' habitats, with reduced representation of insectivores in the latter. In contrast to previous theory regarding trophic cascade strength, we find that birds and bats reduce the density and biomass of arthropods in the tropics with effect sizes similar to those in temperate and boreal communities. The relative importance of birds versus bats in regulating pest abundances varies with season, geography and management. Birds and bats may even suppress tropical arthropod outbreaks, although positive effects on plant growth are not always reported. As both bats and birds are major agents of pest suppression, a better understanding of the local and landscape factors driving the variability of their impact is needed. © 2015 Cambridge Philosophical Society.
Marks E.A.N., Molowny-Horas R., Domene X. (2015) Investigating the Use of Multi-Gaussian Nonlinear Regressions to Separate Collembolan Size Classes for Soil Quality Assessment. Water, Air, and Soil Pollution. 226: 0-0.LinkDoi: 10.1007/s11270-015-2503-6
Previous studies with bioindicator organisms have used somatic length distributions, i.e., population structure, to understand the effects of management, environment, or a potential contaminant on populations. We describe a statistical approach to separate somatic length classes of Folsomia candida juveniles as an endpoint for the assessment of changes in population structure. Reproduction-survival bioassays were carried out with five different biochars applied at increasing concentrations. Multi-Gaussian models parameterized juvenile size class cohorts, and the biomass of each size class cohort was estimated. Population structure was modified by both material type as well as concentration. Both biomass and population structure were sensitive to effects not reflected in juvenile number, the classic endpoint. Treatments with more size classes and larger individuals were taken to represent favorable conditions, and less size classes and smaller individuals indicated less favorable conditions. This extension of the standardized test provided additional information about the demography of the population. © 2015 Springer International Publishing Switzerland.
Martin-Alcon S., Coll L., De Caceres M., Guitart L., Cabre M., Just A., Gonzalez-Olabarria J.R. (2015) Combining aerial LiDAR and multispectral imagery to assess postfire regeneration types in a Mediterranean forest. Canadian Journal of Forest Research. 45: 856-866.LinkDoi: 10.1139/cjfr-2014-0430
Wildfires play a major role in driving vegetation changes and can cause important environmental and economic losses in Mediterranean forests, especially where the dominant species lacks efficient postfire regeneration mechanisms. In these areas, postdisturbance vegetation management strategies need to be based on detailed, spatially continuous inventories of the burned area. Here, we present a methodology in which we combine airborne LiDAR and multispectral imagery to assess postfire regeneration types in a spatially continuous way, using a Mediterranean black pine (Pinus nigra Arn ssp. salzmannii) forest that burned in 1998 as a case study. Five postfire regeneration types were obtained by clustering field-plot data using Ward's method. Two of the five regeneration types presented high tree cover (one clearly dominated by hardwoods and the other dominated by pines), a third type presented low to moderate tree cover, being dominated by hardwoods, and the remaining two types matched to areas dominated by soil–herbaceous or shrub layers with very low or no tree cover (i.e., very low to no tree species regeneration). These five types of regeneration were used to conduct a supervised classification of remote sensing data using a nonparametric supervised classification technique. Compared with independent field validation points, the remote sensing based assessment method resulted in a global classification accuracy of 82.7%. Proportions of regeneration types in the study area indicated a general shift from the former pine-dominated forest toward hardwood dominance and showed no serious problems of regeneration failure. Our methodological approach appears to be appropriate for informing postdisturbance vegetation management strategies over large areas. © 2015, (publisher). All Rights Reserved.
Martin-Alcon S., Coll L., Salekin S. (2015) Stand-level drivers of tree-species diversification in Mediterranean pine forests after abandonment of traditional practices. Forest Ecology and Management. 353: 107-117.LinkDoi: 10.1016/j.foreco.2015.05.022
The progressive abandonment of traditional forest management over the last few decades has led to significant densification processes in most Mediterranean pine stands. In parallel, some of these stands have also shown tree-species diversification processes, the occurrence of which is considered essential for future adaptability and resilience to change. Here we aim to gain further understanding of the main factors driving these diversification processes via a case-study approach using the long-term-managed black pine (Pinus nigra Arn. ssp. salzmannii) forests of the Catalan Pre-Pyrenees (NE Spain). For this purpose, we sampled 155 plots distributed in 8 different stands and analyzed the role played by a number of microsite factors and stand attributes (including canopy openness and heterogeneity) on the abundance of seedlings (h1.3m; dbh
Martin-Gomez P., Barbeta A., Voltas J., Penuelas J., Dennis K., Palacio S., Dawson T.E., Ferrio J.P. (2015) Isotope-ratio infrared spectroscopy: A reliable tool for the investigation of plant-water sources?. New Phytologist. : 0-0.LinkDoi: 10.1111/nph.13376
Summary: Stable isotopes are extensively used as tracers for the study of plant-water sources. Isotope-ratio infrared spectroscopy (IRIS) offers a cheaper alternative to isotope-ratio mass spectroscopy (IRMS), but its use in studying plant and soil water is limited by the spectral interference caused by organic contaminants. Here, we examine two approaches to cope with contaminated samples in IRIS: on-line oxidation of organic compounds (MCM) and post-processing correction. We assessed these methods compared to IRMS across 136 samples of xylem and soil water, and a set of ethanol- and methanol-water mixtures. A post-processing correction significantly improved IRIS accuracy in both natural samples and alcohol dilutions, being effective with concentrations up to 8% of ethanol and 0.4% of methanol. MCM outperformed the post-processing correction in removing methanol interference, but did not effectively remove interference for high concentrations of ethanol. By using both approaches, IRIS can overcome with reasonable accuracy the analytical uncertainties associated with most organic contaminants found in soil and xylem water. We recommend the post-processing correction as the first choice for analysis of samples of unknown contamination. Nevertheless, MCM can be more effective for evaluating samples containing contaminants responsible for strong spectral interferences at low concentrations, such as methanol. © 2015 New Phytologist Trust.
Marull J., Otero I., Stefanescu C., Tello E., Miralles M., Coll F., Pons M., Diana G.L. (2015) Exploring the links between forest transition and landscape changes in the Mediterranean. Does forest recovery really lead to better landscape quality?. Agroforestry Systems. : 0-0.LinkDoi: 10.1007/s10457-015-9808-8
A growing number of studies argue that forest transition should be enhanced by policymakers given its potential benefits, for instance in slowing climate change through carbon sequestration. Yet the effects of forest transition in landscape heterogeneity and biodiversity remain poorly understood. In this paper we explore the relationships between the forest transition and the landscape changes occurred in a Mediterranean mountain area. Historical land-use maps were built from cadastral cartography (1854; 1956; 2012). Metrics on land-cover change, landscape structure, and landscape functioning were calculated. Multiyear data on butterfly assemblages from two transects (1994–2012) was used as indicator of land-use change effects on biodiversity. Results show a forest expansion process in former cereal fields, vineyards and pasturelands along with rural out-migration and land abandonment. Such forest transition involved large changes in landscape structure and functioning. As peasant management of integrated agrosilvopastoral systems disappeared, landscape became less diverse. Even if forest area is now larger than in mid-nineteenth century, ecological connectivity among woodland did not substantially improve. Instead, ecological connectivity across open habitats has greatly decreased as cereal fields, vineyards, meadows and pasturelands have almost disappeared. Butterfly assemblages under changing land-uses highlights the importance of agro-forest mosaics not only for these species but for biodiversity at large in the last decades. Our work emphasizes that conservation of landscapes with a long history of human use needs to take into account the role of humans in shaping ecological features and biodiversity. Hence the suitability of forest transitions should be critically examined in relation to context and policy objectives. © 2015 Springer Science+Business Media Dordrecht
Mayol M., Riba M., Gonzalez-Martinez S.C., Bagnoli F., de Beaulieu J.-L., Berganzo E., Burgarella C., Dubreuil M., Krajmerova D., Paule L., Romsakova I., Vettori C., Vincenot L., Vendramin G.G. (2015) Adapting through glacial cycles: Insights from a long-lived tree (Taxus baccata). New Phytologist. : 0-0.LinkDoi: 10.1111/nph.13496
Despite the large body of research devoted to understanding the role of Quaternary glacial cycles in the genetic divergence of European trees, the differential contribution of geographic isolation and/or environmental adaptation in creating population genetic divergence remains unexplored. In this study, we used a long-lived tree (Taxus baccata) as a model species to investigate the impact of Quaternary climatic changes on genetic diversity via neutral (isolation-by-distance) and selective (isolation-by-adaptation) processes. We applied approximate Bayesian computation to genetic data to infer its demographic history, and combined this information with past and present climatic data to assess the role of environment and geography in the observed patterns of genetic structure. We found evidence that yew colonized Europe from the East, and that European samples diverged into two groups (Western, Eastern) at the beginning of the Quaternary glaciations, c. 2.2 Myr before present. Apart from the expected effects of geographical isolation during glacials, we discovered a significant role of environmental adaptation during interglacials at the origin of genetic divergence between both groups. This process may be common in other organisms, providing new research lines to explore the effect of Quaternary climatic factors on present-day patterns of genetic diversity. © 2015 New Phytologist Trust.
Meir P., Mencuccini M., Dewar R.C. (2015) Drought-related tree mortality: Addressing the gaps in understanding and prediction. New Phytologist. 207: 28-33.LinkDoi: 10.1111/nph.13382
Increased tree mortality during and after drought has become a research focus in recent years. This focus has been driven by: the realisation that drought-related tree mortality is more widespread than previously thought; the predicted increase in the frequency of climate extremes this century; and the recognition that current vegetation models do not predict drought-related tree mortality and forest dieback well despite the large potential effects of these processes on species composition and biogeochemical cycling. To date, the emphasis has been on understanding the causal mechanisms of drought-related tree mortality, and on mechanistic models of plant function and vegetation dynamics, but a consensus on those mechanisms has yet to emerge. In order to generate new hypotheses and to help advance the modelling of vegetation dynamics in the face of incomplete mechanistic understanding, we suggest that general patterns should be distilled from the diverse and as-yet inconclusive results of existing studies, and more use should be made of optimisation and probabilistic modelling approaches that have been successfully applied elsewhere in plant ecology. The outcome should inform new empirical studies of tree mortality, help improve its prediction and reduce model complexity. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.
Melero Y., Robinson E., Lambin X. (2015) Density- and age-dependent reproduction partially compensates culling efforts of invasive non-native American mink. Biological Invasions. 17: 2645-2657.LinkDoi: 10.1007/s10530-015-0902-7
Management strategies of wildlife species must pay due regard to density dependent changes in vital rates. Knowledge of density dependent relationships is sparse for most species but such knowledge ought to inform adaptive management. Using data from a large-scale, 6 years of control effort of the invasive non-native American mink (Neovison vison) in Scotland, we analysed density dependent changes in reproduction as revealed by placental scar counts in culled females. Control strongly reduced mink density but it varied substantially over time and space, reflecting variation in when control was initiated in each river section. We used hurdle statistical models to simultaneously relate the probability of conception, litter size and female age to prevailing mink density in river sections where the female was culled. Both the probability of conceiving a litter (average 0.81) and litter size (average 5.52 pups) increased as the density of females, but not males, declined. In addition, there was a senescent decline in both components of fecundity, which given culling of mink and subsequent reinvasions, resulted in a younger population, adding further to density dependent compensation in fecundity. There was no evidence of depensation, even at the lowest density. The predicted combined impact of changes in density and age structure could lead to an increase in fecundity of up to 2.1 pups per female occupying or reinvading the controlled area. Control strategies must be sufficiently adaptable and robust in order to overcome this compensation and suppress densities of mink and other invasive mammals. © 2015, Springer International Publishing Switzerland.
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