We examined the predictability of fire days in a seasonally dry tropical forest in southern India using weather parameters. Fire days were more likely with low rainfall in the early dry season, low relative humidity and high temperatures during the dry season. We provide a quantitative framework for fire risk assessment for this forest type.
Publication date: May 2014 Source:Biological Conservation, Volume 173 Author(s): Mark J. Costello , John Wieczorek There is increasing pressure from the scientific community, including funding agencies, journals and peers, for authors to publish the biodiversity data used in published articles and other scientific literature. This enables reproducibility of research and creates new opportunities for integrating data between research projects and analysing data in additional ways. The long-term availability of data is especially important in conservation science because field data can be costly to collect. In addition, historic data, especially on threatened species and their associated biota, become more valuable over time. This paper summarises current standards and best practices for the management and publication of biodiversity data. It includes recommendations for citing sources of species determination and standards for formatting species distribution data. Whenever possible, data should be published for inclusion in data access platforms that integrate datasets (e.g. GBIF, GenBank) and so enable new analyses and broader impact. Data centres (e.g. PANGAEA) provide added value in quality checks on data. A minimum standard recommended is that data should be permanently archived in an online, open-access repository with sufficient metadata for potential users to understand how and why they were collected.
by Elizabeta Briski, Farrah T. Chan, Hugh J. MacIsaac, Sarah A. Bailey
Abstract
Aim
After J. L. Lockwood, P. Cassey and T. Blackburn (2009, Diversity and Distributions, 15, 904–910) first described a theoretical relationship between propagule pressure and colonization pressure, two empirical studies demonstrated that the transport stage of the invasion process can profoundly influence the strength of the relationship among multiple events, as well as predictions of introduction risk. However, studies exploring dynamics of transported communities are rare, as repeated-measures sampling during transportation by any vector is logistically difficult. We constructed a conceptual model of community dynamics during transportation and supported it by empirical data for propagule pressure and colonization pressure of plankton.
Location
Global.
Methods
A conceptual model of community dynamics was developed based on lognormal species abundance distribution and the simulation model of J. L. Lockwood, P. Cassey and T. Blackburn (2009, Diversity and Distributions, 15, 904–910). We considered four cases: case ‘A’ – no reduction in propagule nor colonization pressure; case ‘B’ – strong reduction in propagule and mild reduction in colonization pressure; case ‘C’ – mild reduction in propagule and strong reduction in colonization pressure; and case ‘D’ – strong reduction in both propagule and colonization pressures.
Results
The cases ‘B’, ‘C’ and ‘D’ were supported by empirical data for invertebrates, dinoflagellates and diatoms from ships’ ballast tanks, respectively. Propagule pressure of invertebrates, dinoflagellates and diatoms decreased 99.95%, 80% and 94% in 25 days, respectively, while colonization pressure decreased 34%, 57% and 64%.
Main conclusions
Transport affects both propagule pressure and colonization pressure of taxa, with the magnitude of change dependent on length of transport and taxon-specific survival and reproduction. Our model demonstrates that introduction risk varies substantially across and within taxa depending on the occurrence and severity of selection pressures during transportation which serve to change species abundance distributions.
by Cynthia A. Froyd, Emily E. D. Coffey, Willem O. Knaap, Jacqueline F. N. Leeuwen, Alan Tye, Katherine J. Willis
Abstract
The giant tortoises of the Galápagos have become greatly depleted since European discovery of the islands in the 16th Century, with populations declining from an estimated 250 000 to between 8000 and 14 000 in the 1970s. Successful tortoise conservation efforts have focused on species recovery, but ecosystem conservation and restoration requires a better understanding of the wider ecological consequences of this drastic reduction in the archipelago's only large native herbivore. We report the first evidence from palaeoecological records of coprophilous fungal spores of the formerly more extensive geographical range of giant tortoises in the highlands of Santa Cruz Island. Upland tortoise populations on Santa Cruz declined 500–700 years ago, likely the result of human impact or possible climatic change. Former freshwater wetlands, a now limited habitat-type, were found to have converted to Sphagnum bogs concomitant with tortoise loss, subsequently leading to the decline of several now-rare or extinct plant species.
by Tomas Roslin, Gergely Várkonyi, Martti Koponen, Veli Vikberg, Marko Nieminen
That larger areas will typically host more diverse ecological assemblages than small ones has been regarded as one of the few fundamental ‘laws’ in ecology. Yet, area may affect not only species diversity, but also the trophic structure of the local ecological assemblage. In this context, recent theory on trophic island biogeography offers two clear-cut predictions: that the slope of the species–area relationship should increase with trophic rank, and that food chain length (i.e. the number of trophic levels) should increase with area. These predictions have rarely been verified in terrestrial systems. To offer a stringent test of key theory, we focused on local food chains consisting of trophic specialists: plants, lepidopteran herbivores, and their primary and secondary parasitoids. For each of these four trophic levels, we surveyed species richness across a set of 20 off-shore continental islands spanning a hundred-fold range in size. We then tested three specific hypotheses: that species richness is affected by island size, that the slope of the species–area curve is related to trophic rank, and that such differences in slope translate into variation in food chain length with island size. Consistent with these predictions, estimates of the species–area slope steepened from plants through herbivores and primary parasitoids to secondary parasitoids. As a result of the elevated sensitivity of top consumers to island size, food chain length decreased from large to small islands. Since island size did not detectably affect the ratio between generalists and specialists among either herbivores (polyphages vs oligophages) or parasitoids (idiobionts vs koinobionts), the patterns observed seemed more reflective of changes in the overall number of nodes and levels in local food webs than of changes in their linking structure. Overall, our results support the trophic-level hypothesis of island biogeography. Per extension, they suggest that landscape modification may imperil food web integrity and vital biotic interactions.
Publication date: January 2014 Source:Biological Conservation, Volume 169 Author(s): Camila Righetto Cassano , Jos Barlow , Renata Pardini Changes in biodiversity and ecosystem services in terrestrial systems are being driven by the synergistic interactions between the loss of native vegetation and land-use intensification. Disentangling the influence of these two processes on species persistence is an important step towards reconciling conservation and agriculture production. We investigated how forest cover and management intensification affect the conservation value of cacao agroforests for mammals in an Atlantic forest landscape in southern Bahia, the most extensive area of diverse shaded cacao plantations in Brazil. Although both factors affected the distribution of mammal species, management intensification had a stronger effect, negatively affecting a larger number of species. Frequency of domestic dogs, an indirect aspect of management intensification, negatively affected four species and lower connectivity of shading trees decreased the use of cacao agroforests by three species of conservation concern. In comparison, the reduced forest cover negatively affected two species of conservation concern. Our results suggest that controlling domestic dog populations is particularly valuable for large mammal conservation in agroforestry mosaics, since it does not affect crop productivity. Improving shade cover within agroforests, on the other hand, should be implemented carefully, maintaining acceptable yield while promoting canopy connectivity and the recruitment of tree species used by forest dependent mammals. However, the importance of both local management intensification and local forest cover are likely to be context dependent, and changes in their relative importance are likely to occur with different levels of deforestation at the landscape scale.
by Silvio Schueler, Wolfgang Falk, Jarkko Koskela, François Lefèvre, Michele Bozzano, Jason Hubert, Hojka Kraigher, Roman Longauer, Ditte C. Olrik
Abstract
A transnational network of genetic conservation units for forest trees was recently documented in Europe aiming at the conservation of evolutionary processes and the adaptive potential of natural or man-made tree populations. In this study, we quantified the vulnerability of individual conservation units and the whole network to climate change using climate favourability models and the estimated velocity of climate change. Compared to the overall climate niche of the analysed target species populations at the warm and dry end of the species niche are underrepresented in the network. However, by 2100, target species in 33–65 % of conservation units, mostly located in southern Europe, will be at the limit or outside the species' current climatic niche as demonstrated by favourabilities below required model sensitivities of 95%. The highest average decrease in favourabilities throughout the network can be expected for coniferous trees although they are mainly occurring within units in mountainous landscapes for which we estimated lower velocities of change. Generally, the species-specific estimates of favourabilities showed only low correlations to the velocity of climate change in individual units, indicating that both vulnerability measures should be considered for climate risk analysis. The variation in favourabilities among target species within the same conservation units is expected to increase with climate change and will likely require a prioritization among co-occurring species. The present results suggest that there is a strong need to intensify monitoring efforts and to develop additional conservation measures for populations in the most vulnerable units. Also, our results call for continued transnational actions for genetic conservation of European forest trees, including the establishment of dynamic conservation populations outside the current species distribution ranges within European assisted migration schemes.
by Cory Merow, Johan P. Dahlgren, C.J.E. Metcalf, Dylan Z. Childs, M.E.K. Evans, E. Jongejans, Sydne Record, Mark Rees, Roberto Salguero-Gómez, Sean M. McMahon
Summary
Integral projection models (IPMs) use information on how an individual's state influences its vital rates – survival, growth and reproduction – to make population projections. IPMs are constructed from regression models predicting vital rates from state variables (e.g. size or age) and covariates (e.g. environment). By combining regressions of vital rates, an IPM provides mechanistic insight into emergent ecological patterns such as population dynamics, species geographic distributions or life-history strategies.
Here, we review important resources for building IPMs and provide a comprehensive guide, with extensive R code, for their construction. IPMs can be applied to any stage-structured population; here, we illustrate IPMs for a series of plant life histories of increasing complexity and biological realism, highlighting the utility of various regression methods for capturing biological patterns. We also present case studies illustrating how IPMs can be used to predict species' geographic distributions and life-history strategies.
IPMs can represent a wide range of life histories at any desired level of biological detail. Much of the strength of IPMs lies in the strength of regression models. Many subtleties arise when scaling from vital rate regressions to population-level patterns, so we provide a set of diagnostics and guidelines to ensure that models are biologically plausible. Moreover, IPMs can exploit a large existing suite of analytical tools developed for matrix projection models.
In order to understand how changes in individual performance (growth, survival or reproduction) influence population dynamics and evolution, ecologists are increasingly using parameterized mathematical models.
For continuously structured populations, where some continuous measure of individual state influences growth, survival or reproduction, integral projection models (IPMs) are commonly used.
We provide a detailed description of the steps involved in constructing an IPM, explaining how to: (i) translate your study system into an IPM; (ii) implement your IPM; and (iii) diagnose potential problems with your IPM. We emphasize how the study organism's life cycle, and the timing of censuses, together determine the structure of the IPM kernel and important aspects of the statistical analysis used to parameterize an IPM using data on marked individuals.
An IPM based on population studies of Soay sheep is used to illustrate the complete process of constructing, implementing and evaluating an IPM fitted to sample data.
We then look at very general approaches to parameterizing an IPM, using a wide range of statistical techniques (e.g. maximum likelihood methods, generalized additive models, nonparametric kernel density estimators). Methods for selecting models for parameterizing IPMs are briefly discussed.
We conclude with key recommendations and a brief overview of applications that extend the basic model. The online Supporting Information provides commented R code for all our analyses.
A detailed description of the steps involved in constructing an IPM, explaining how to: (i) translate your study system into an IPM; (ii) implement your IPM; and (iii) diagnose potential problems with your IPM. We emphasize how the study organism's life cycle, and the timing of censuses, together determine the structure of the IPM kernel and important aspects of the statistical analysis used to parameterise an IPM using data on marked individuals.
Current developments of diversity measures that consider that species are not equivalent, concentrate on how functionally or phylogenetically (dis)similar species are from each other (interspecific components). To assess the biodiversity of a community, few of the developed measures include intraspecific components, that is to say components that concern only the current features of the individuals of a species or the history of the species regardless of the other extant species of the community. A requirement for new developments in diversity indices could thus be to integrate both interspecific and intraspecific components. The objectives of our study are to introduce a parametric index of diversity (qH), expressed as an effective number of species, which satisfies this requirement, and to analyse the diversity of order 2 (2H). In the particular case of equal intraspecific components for every species, 2H is a simple function of Rao's quadratic entropy.
We introduce our new index family and demonstrate that the vectors of species' proportions that maximize 2H are not necessarily unique and may have zeros (removing species). Then, we apply our index to two case studies: a theoretical example of phylogenetic diversity analysis; and a real data set on the changes in diet diversity of bird communities along an altitudinal gradient.
Using a theoretical phylogenetic tree, we demonstrate that a maximizing vector for 2H can be associated with measures of species' phylogenetic originality. Applied to bird communities in Tarentaise Valley, France, 2H describes a decline in diet diversity with altitude due to a higher proportion of invertebrates in the diets of birds that occur where rocks replace deciduous and evergreen bushes and trees.
Related to recent developments of diversity study made in the field of ecology, our approach has the advantages of integrating functional or phylogenetic intraspecific and interspecific components, and species' proportions (e.g. relative abundance or biomass), and of being applicable to many different data sets and objectives. Applied to both phylogenetic and functional diversity, our approach can help decisions when prioritizing conservation actions.
by Gill, J. A., Alves, J. A., Sutherland, W. J., Appleton, G. F., Potts, P. M., Gunnarsson, T. G.
Recent advances in spring arrival dates have been reported in many migratory species but the mechanism driving these advances is unknown. As population declines are most widely reported in species that are not advancing migration, there is an urgent need to identify the mechanisms facilitating and constraining these advances. Individual plasticity in timing of migration in response to changing climatic conditions is commonly proposed to drive these advances but plasticity in individual migratory timings is rarely observed. For a shorebird population that has significantly advanced migration in recent decades, we show that individual arrival dates are highly consistent between years, but that the arrival dates of new recruits to the population are significantly earlier now than in previous years. Several mechanisms could drive advances in recruit arrival, none of which require individual plasticity or rapid evolution of migration timings. In particular, advances in nest-laying dates could result in advanced recruit arrival, if benefits of early hatching facilitate early subsequent spring migration. This mechanism could also explain why arrival dates of short-distance migrants, which generally return to breeding sites earlier and have greater scope for advance laying, are advancing more rapidly than long-distance migrants.
Can bushfire activity be forecast using climate variables? We review the relationship between fire activity, climate variables and El Niño–Southern Oscillation (ENSO) for the fire-prone state of Victoria, Australia. The results reveal the potential to use climate variables and ENSO indices to forecast the upcoming season’s potential bushfire activity.
by onlinepublishing@allenpress.com (F. Guillaume Blanchet et al)
Ecological Monographs, Volume 84, Issue 3, Page 491-511, August 2014.
Understanding how habitat structures species assemblages in a community is one of the main goals of community ecology. To relate community patterns to particular factors defining habitat conditions, ecologists often use canonical ordinations such as canonical redundancy analysis (RDA). It is a common practice to use dissimilarity coefficients to perform canonical ordinations through distance-based RDA (db-RDA) or transformation-based RDA (tb-RDA). Dissimilarity coefficients are measures of resemblance where the information about species communities is condensed into a symmetric square matrix of dissimilarities among sites. In this study, we compared 16 of the most commonly used dissimilarity coefficients to evaluate if the species-abundance distribution (SAD) of a community can be used to select an appropriate coefficient. Of these, 11 are designed to be used primarily with abundance data, although they can also be used with presence–absence data, whereas five can only be applied to presence–absence data. Using simulations, we compared the explained variance of RDAs differing only by their coefficients to evaluate how the abundance patterns of communities influence coefficient choice. We found that coefficients are largely equivalent, independently of the community SAD. In light of these findings, we propose the consensus RDA method, a new canonical ordination procedure that performs a consensus of RDAs across several coefficients. This new method focuses on the common relations found by independent RDAs differing only by their dissimilarity coefficients; this ensures the absence of a coefficient-related bias when interpreting the canonical ordination result. Also, because in our simulations the presence–absence data were directly derived from the abundance data, we were able to evaluate if the information in presence–absence data was equivalent to that in abundance data. We found that although some information was lost by converting abundance data into presence–absence, both data formats may be complementary. When applying consensus RDA to abundance and presence–absence data independently, a more complete understanding and interpretation of the ecological patterns is obtained. An ecological example illustrating consensus RDA and the conclusions of our simulations is presented, using Carabidae data collected at the Ecosystem Management Emulating Natural Disturbances (EMEND) project in northwestern Alberta, Canada.
Zachary J. Nelson, Peter J. Weisberg, Stanley G. Kitchen - Volume 23(1)
Fire-killed plants must recover by seed or resprouting. In semi-arid environments this depends on episodic wet periods for establishment. We found the widespread shrub sagebrush recovered faster when fire was followed by wet winters. Sagebrush ecosystems may undergo dramatic transformation if the frequency of consecutive drought years increases.
Txomin Hermosilla, Luis A. Ruiz, Alexandra N. Kazakova, Nicholas C. Coops, L. Monika Moskal
Knowledge of fuel conditions is critical to accurately forecast fire behaviour. We present a methodology to estimate forest canopy fuel parameters using small-footprint, full-waveform light detection and ranging (LiDAR) airborne data in a mixed forest region of north-west Oregon (US).
by Shannon J. McCauley, Christopher J. Davis, Earl E. Werner, Michael S. Robeson II
Summary
Species' range sizes are shaped by fundamental differences in species' ecological and evolutionary characteristics, and understanding the mechanisms determining range size can shed light on the factors responsible for generating and structuring biological diversity. Moreover, because geographic range size is associated with a species' risk of extinction and their ability to respond to global changes in climate and land use, understanding these mechanisms has important conservation implications.
Despite the hypotheses that dispersal behaviour is a strong determinant of species range areas, few data are available to directly compare the relationship between dispersal behaviour and range size. Here, we overcome this limitation by combining data from a multispecies dispersal experiment with additional species-level trait data that are commonly hypothesized to affect range size (e.g. niche breadth, local abundance and body size.). This enables us to examine the relationship between these species-level traits and range size across North America for fifteen dragonfly species.
Ten models based on a priori predictions about the relationship between species traits and range size were evaluated and two models were identified as good predictors of species range size. These models indicated that only two species' level traits, dispersal behaviour and niche breadth were strongly related to range size. The evidence from these two models indicated that dragonfly species that disperse more often and further had larger North American ranges.
Extinction and colonization dynamics are expected to be a key linkage between dispersal behaviour and range size in dragonflies. To evaluate how extinction and colonization dynamics among dragonflies were related to range size we used an independent data set of extinction and colonization rates for eleven dragonfly species and assessed the relationship between these populations rates and North American range areas for these species.
We found a negative relationship between North American range size and species' extinction-to-colonization ratios. Our results indicate that metapopulation dynamics act to shape the extent of species' continental distributions. These population dynamics are likely to interact with dispersal behaviour, particularly at species range margins, to determine range limits and ultimately species range sizes.
Species range size affects their risk of extinction and can shape their response to climate change. This study of range size in dragonflies reveals that species traits and population dynamics are related to their range size, more dispersive species and those with higher colonization to extinction ratios had larger ranges.
by onlinepublishing@allenpress.com (Shawn M. Crimmins et al)
Ecological Applications, Volume 24, Issue 5, Page 1057-1069, July 2014.
Correlative species distribution models (SDMs) are widely used in studies of climate change impacts, yet are often criticized for failing to incorporate disturbance processes that can influence species distributions. Here we use two temporally independent data sets of vascular plant distributions, climate data, and fire atlas data to examine the influence of disturbance history on SDM projection accuracy through time in the mountain ranges of California, USA. We used hierarchical partitioning to examine the influence of fire occurrence on the distribution of 144 vascular plant species and built a suite of SDMs to examine how the inclusion of fire-related predictors (fire occurrence and departure from historical fire return intervals) affects SDM projection accuracy. Fire occurrence provided the least explanatory power among predictor variables for predicting species' distributions, but provided improved explanatory power for species whose regeneration is tied closely to fire. A measure of the departure from historic fire return interval had greater explanatory power for calibrating modern SDMs than fire occurrence. This variable did not improve internal model accuracy for most species, although it did provide marginal improvement to models for species adapted to high-frequency fire regimes. Fire occurrence and fire return interval departure were strongly related to the climatic covariates used in SDM development, suggesting that improvements in model accuracy may not be expected due to limited additional explanatory power. Our results suggest that the inclusion of coarse-scale measures of disturbance in SDMs may not be necessary to predict species distributions under climate change, particularly for disturbance processes that are largely mediated by climate.
by Anett Schibalski, Aleksi Lehtonen, Boris Schröder
Our study aims at gaining insights into the processes determining the current treeline dynamics in Finnish Lapland. Using forest surveys conducted in 1978 and 2003 we modelled the occurrence and abundance of three dominant tree species in Finnish Lapland, i.e. Pinus sylvestris, Picea abies and Betula pubescens, with boosted regression trees. We assessed the importance of climatic, biotic and topographic variables in predicting tree occurrence and abundance based on their relative importance and response curves. We compared temporal and spatial transferability by using an extended transferability index.
Site fertility, the abundance of co-occurring species and growing degree days were generally the most important predictors for both occurrence and abundance across all species and datasets. Climatic predictors were more important for modelling occurrences than for modelling abundances. Occurrence models were able to reproduce the observed treeline pattern within one time period or region. Abundance models underestimated basal area but captured the general pattern of low and high values. Model performance as well as transferability differed considerably between species and datasets. Pinus sylvestris was modelled more successfully than P. abies and B. pubescens. Generally, spatial transferability was greater than temporal transferability. Comparing the environmental space between datasets revealed that transferring models means extrapolating to novel environments, providing a plausible explanation for limited transferability.
Our study illustrates how climate change can shift the environmental space and lead to limited model transferability. We identified non-climatic factors to be important in predicting the distribution of dominant tree species, contesting the widespread assumption of climatically induced range expansion.
A comparison of the conservation status of the breeding birds of Catalonia between 2002 and 2012 has revealed an improvement of 4% in the Red List Index.
Title: Changes in the conservation status of the breeding birds in Catalonia (NE Iberian Peninsula) in the period 2002-2012
Authors: Sergi Herrando, Marc Anton E-mail: ornitologia[at]ornitologia.org Abstract: The first assessment of the conservation status of breeding birds in Catalonia was made in 2002 on the basis of their population sizes and distributions and the changes in these two parameters that had occurred since the 1980s to the beginning of the 2000s. A second assessment was recently made, taking into account the situation of the population sizes and distributions in 2012 and changes occurred during the period 2002-2012. Since both assessments were made according to the criteria of the International Union for Conservation of Nature (IUCN), it has been possible to study the change in conservation status applying the Red List Index, the indicator recommended by this international body for this purpose. A key point of this methodology is to determine genuine changes in status and differentiate them from those associated with variations in the level of knowledge or modifications in the evaluation criteria. Once this was taken into account we applied the Red List Index (RLI) algorithm using 155 species (67% of bird species breeding in Catalonia) both for 2002 and 2012. The index showed an improvement of the threat status by 4% during this 10-year period. In addition, we re-evaluated the 2002 status with updated criteria and knowledge and applied the same algorithm to calculate a second index (re-RLI) for 232 (all breeding species). The re-RLI improved by 5% during this decade. The results suggest a general improvement in the overall conservation status of birds breeding in Catalonia during the last 10 years.
Títol: Canvis en l’estatus de conservació dels ocells nidificants a Catalunya (NE península Ibèrica) en el període 2002-2012
Autors: Sergi Herrando, Marc Anton E-mail: ornitologia[at]ornitologia.org Resum: La primera avaluació de l’estat de conservació dels ocells reproductors de Catalunya es va dur a terme l’any 2002 a partir de la situació que mostraven les poblacions de les espècies ençà i els canvis ocorreguts des dels anys 80 del darrer segle. Recentment, s’ha fet una actualització de l’estat de conservació a partir de les estimes poblacionals i distribucions l’any 2012 i dels canvis ocorreguts en el període 2002-2012. Degut a què ambdues avaluacions s’han fet seguint els criteris de la Unió Internacional per a la Conservació de la Natura (IUCN), ens ha estat possible l’estudi del canvi d’estatus aplicant l’Índex de la Llista Vermella (RLI), l’indicador recomanat per aquest organisme internacional per determinar els canvis en l’estatus de conservació. Un factor clau d’aquest metodologia és distingir els canvis reals d’aquells associats a canvis en el grau de coneixement de les espècies o modificacions en els criteris d’avaluació. Un cop això es va tenir en consideració, es va aplicar l’algoritme del RLI per a 155 espècies (67% de les espècies nidificants a Catalunya) per al 2002 i 2012. Aquest índex va mostrar una millora del 4% en aquest període. A més, i com a procediment alternatiu, es van re-avaluar els estatus 2002 amb criteris i dades actualitzades i es va aplicar el mateix algoritme per a calcular un segon índex, anomenat re-RLI, per a 232 espècies (totes les espècies nidificants). Aquest segon índex també va millorar (5%) durant aquesta dècada. Aquests resultats suggereixen una millora general en l’estat de conservació dels ocells nidificants a Catalunya en els darrers 10 anys.
Título: Cambios en el estatus de conservación de las aves reproductoras de Cataluña (NE península Ibérica) en el periodo 2002-2012
Autores: Sergi Herrando, Marc Anton E-mail: ornitologia[at]ornitologia.org Resumen: La primera evaluación del estatus de conservación de las aves reproductoras de Cataluña se llevó a cabo en el año 2002 a partir de la situación que mostraban las poblaciones de las especies en aquel momento y de los cambios ocurridos desde los años 80 del último siglo. Recientemente, se ha hecho una actualización del estado de conservación de las aves para el periodo 2002-2012. Debido a que ambas evaluaciones se han realizado siguiendo los criterios de la Unión Internacional para la Conservación de la Naturaleza (IUCN), nos ha sido posible el estudio del cambio de estatus aplicando el Índice de Lista Roja (RLI), el indicador recomendado por este organismo internacional para determinar los cambios en el estatus de conservación. Un factor clave de esta metodología es distinguir los cambios reales de aquellos artefactuales asociados a cambios en el grado de conocimiento de las especies o modificaciones en los criterios de evaluación. Una vez esto se tuvo en consideración, se aplicó el algoritmo del RLI para un 155 especies (67% de las especies reproductoras en Cataluña) para el 2002 y 2012. Este índice mostró una mejora del 4% en este periodo de 10 años. Además, y como procedimiento alternativo, se re-evaluaron los estatus 2002 con criterios y datos actualizados y se aplicó el mismo algoritmo para calcular un segundo índice, llamado re-RLI, para 232 especies (todas las especies reproductoras). Este segundo índice también mejoró (5%) durante esta década. Estos resultados sugieren una mejora general en el estado de conservación de las aves reproductoras en Cataluña en los últimos 10 años.
by Blas M. Benito, Juan Lorite, Ramón Pérez-Pérez, Lorena Gómez-Aparicio, Julio Peñas
Abstract
Aim
The Mediterranean Basin is threatened by climate change, and there is an urgent need for studies to determine the risk of plant range shift and potential extinction. In this study, we simulate potential range shifts of 176 plant species to perform a detailed prognosis of critical range decline and extinction in a transformed mediterranean landscape. Particularly, we seek to answer two pivotal questions: (1) what are the general plant-extinction patterns we should expect in mediterranean landscapes during the 21st century? and (2) does dispersal ability prevent extinction under climate change?
Location
Andalusia: southern Iberian Peninsula; 87,597 km2; 300 by 520 km.
Methods
We gathered information on the dispersal traits of 176 plant species (dispersal vector, average and maximum dispersal distances, shape of the dispersal kernel). We used these data to feed a stochastic dynamic species distribution model (a combination of a cellular automaton with an ensemble of species distribution models) to simulate plant range shift under climate change with realistic dispersal under two different warming scenarios. We compared dispersal and non-dispersal simulations to assess the influence that climate change and species-distribution characteristics exert on plant-extinction patterns.
Results
The dispersal simulation showed a lower percentage of extinct (−1%) and quasi-extinct species (−19%) than did the non-dispersal simulation. Summer temperatures of 37 °C and 33 °C, respectively, accelerated the critical range decline and extinction rates. The average elevation of the plant populations was the variable with the highest influence on extinction probability.
Main conclusions
Stochastic dynamic species distribution models proved to be useful when there was lack of data on dispersal distances and population dynamics. Dispersal ability showed minor effectiveness in preventing extinction, but greatly reduced the likelihood of critical range decline for a significant percentage of species.
by Catherine S. Jarnevich, Wayne E. Esaias, Peter L. A. Ma, Jeffery T. Morisette, Jaime E. Nickeson, Thomas J. Stohlgren, Tracy R. Holcombe, Joanne M. Nightingale, Robert E. Wolfe, Bin Tan
Abstract
Aim
Species distribution models have often been hampered by poor local species data, reliance on coarse-scale climate predictors and the assumption that species–environment relationships, even with non-proximate predictors, are consistent across geographical space. Yet locally accurate maps of invasive species, such as the Africanized honeybee (AHB) in North America, are needed to support conservation efforts. Current AHB range maps are relatively coarse and are inconsistent with observed data. Our aim was to improve distribution maps using more proximate predictors (phenology) and using regional models rather than one across the entire range of interest to explore potential differences in drivers.
Location
United States of America.
Methods
We provide a generalized framework for regional and local species distribution modelling with our more nuanced and spatially detailed forecast of potential AHB spread using multiple habitat modelling techniques and newly derived remotely sensed phenology layers.
Results
Variable importance did differ between the two regions for which we modelled AHB. Phenology metrics were important, especially in the south-east.
Main conclusions
Results demonstrate that incorporating a combination of both climate drivers and vegetation phenology information into models can be important for predicting the suitable habitat range of these pollinators. Regional models may provide evidence of differing drivers of distributions geographically. This framework may improve many local and regional species distribution modelling efforts.
Publication date: December 2013 Source:Biological Conservation, Volume 168 Author(s): Maria Triviño , Mar Cabeza , Wilfried Thuiller , Thomas Hickler , Miguel B. Araújo Conservation priority areas and programs are often established without consideration of future changes in species distributions. However, global change is expected to threaten the persistence of several species while offering opportunities for range expansion to others. In this study, building on previous work, we develop and implement an approach to classify bird species according to their degree of exposure and vulnerability to future climate and land-use change, including climatically driven changes in vegetation. To examine species exposure to environmental changes, we first fitted environmental envelope models and projected then into the future under scenarios of climate, land use and vegetation change. Then, we estimated species vulnerability by taking into account traits that are expected to render species vulnerable to environmental change while considering, simultaneously, the current IUCN conservation status of species. Our results show that bird species highly (and negatively) exposed to future environmental changes are currently less threatened and possess characteristics that render them less susceptible to local extinction than species that are less exposed. Our results reinforce the need to complement studies of global change impacts on biodiversity, typically based on assessments of species exposure to changes, with additional information related to the ability of species to persist under such changes. Nevertheless, we stress that while combining different sources of information is important, it is the comparison of outcomes from these different sources of information that enables development of alternative management strategies. Depending on the source of risk (e.g., exposure to global change versus vulnerability traits to multiple stressors) alternative conservation actions might be required.
Publication date: December 2013 Source:Biological Conservation, Volume 168 Author(s): Matthew J. Smith , Graham J. Forbes , Matthew G. Betts Reduced movement across a landscape due to habitat loss and fragmentation is considered one of the primary reasons for species’ population declines. Gliding mammals, such as the northern flying squirrel (Glaucomys sabrinus), are expected to be particularly sensitive to large non-forested gaps and therefore have been used as umbrella species in planning for landscape connectivity. We tested the gap-crossing decisions of the northern flying squirrel in a forested landscape in southern New Brunswick, Canada. We translocated 35 flying squirrels across non-forested gaps (50–960m) with varying detour efficiency (distance to return home across the gap divided by the forested detour distance) and recorded the individual movement paths to return home. We found that 69% of flying squirrels took the forested route home and avoided crossing gaps. Detour efficiency was the only significant landscape predictor of gap-crossing; for every 1% increase in detour efficiency the odds of flying squirrels detouring were 15% higher. Northern flying squirrels were much more likely to take forested routes than to cross open canopy gaps, even when the direct distance was 6.8 times shorter. In addition, flying squirrels took substantially longer to return home if gaps in forest cover exceed a threshold of 335m. Such threshold responses by flying squirrels could partly explain observed drops in flying squirrel occurrence in small, isolated patches of forest. Avoidance of gaps when detours are cheap suggests that there is a cost associated with crossing gaps. This provides support for the importance of maintaining functional connectivity in forested landscapes.
by Boulangeat Isabelle, Georges Damien, Thuiller Wilfried
Abstract
During the last decade, despite strenuous efforts to develop new models and compare different approaches, few conclusions have been drawn on their ability to provide robust biodiversity projections in an environmental change context. The recurring suggestions are that models should explicitly (i) include spatiotemporal dynamics; (ii) consider multiple species in interactions and (iii) account for the processes shaping biodiversity distribution. This article presents a biodiversity model (FATE-HD) that meets this challenge at regional scale by combining phenomenological and process-based approaches and using well-defined plant functional groups. FATE-HD has been tested and validated in a French National Park, demonstrating its ability to simulate vegetation dynamics, structure and diversity in response to disturbances and climate change. The analysis demonstrated the importance of considering biotic interactions, spatio-temporal dynamics and disturbances in addition to abiotic drivers to simulate vegetation dynamics. The distribution of pioneer trees was particularly improved, as were all undergrowth functional groups.
by Camille Albouy, Laure Velez, Marta Coll, Francesco Colloca, François Loc'h, David Mouillot, Dominique Gravel
Abstract
Climate change is inducing deep modifications in species geographic ranges worldwide. However, the consequences of such changes on community structure are still poorly understood, particularly the impacts on food-web properties. Here, we propose a new framework, coupling species distribution and trophic models, to predict climate change impacts on food-web structure across the Mediterranean Sea. Sea surface temperature was used to determine the fish climate niches and their future distributions. Body size was used to infer trophic interactions between fish species. Our projections reveal that 54 fish species of 256 endemic and native species included in our analysis would disappear by 2080–2099 from the Mediterranean continental shelf. The number of feeding links between fish species would decrease on 73.4% of the continental shelf. However, the connectance of the overall fish web would increase on average, from 0.26 to 0.29, mainly due to a differential loss rate of feeding links and species richness. This result masks a systematic decrease in predator generality, estimated here as the number of prey species, from 30.0 to 25.4. Therefore, our study highlights large-scale impacts of climate change on marine food-web structure with potential deep consequences on ecosystem functioning. However, these impacts will likely be highly heterogeneous in space, challenging our current understanding of climate change impact on local marine ecosystems.
by Trevor H. Booth, Henry A. Nix, John R. Busby, Michael F. Hutchinson
Abstract
Aim
Interest in species distribution models (SDMs) and related niche studies has increased dramatically in recent years, with several books and reviews being prepared since 2000. The earliest SDM studies are dealt with only briefly even in the books. Consequently, many researchers are unaware of when the first SDM software package (bioclim) was developed and how a broad range of applications using the package was explored within the first 8 years following its release. The purpose of this study is to clarify these early developments and initial applications, as well as to highlight bioclim's continuing relevance to current studies.
Location
Mainly Australia and New Zealand, but also some global applications.
Methods
We outline the development of the bioclim package, early applications (1984–1991) and its current relevance.
Results
bioclim was the first SDM package to be widely used. Early applications explored many of the possible uses of SDMs in conservation biogeography, such as quantifying the environmental niche of species, identifying areas where a species might be invasive, assisting conservation planning and assessing the likely impacts of climate change on species distributions.
Main conclusions
Understanding this pioneering work is worthwhile as bioclim was for many years one of the leading SDM packages and remains widely used. Climate interpolation methods developed for bioclim were used to create the WorldClim database, the most common source of climate data for SDM studies, and bioclim variables are used in about 76% of recent published MaxEnt analyses of terrestrial ecosystems. Also, some of the bioclim studies from the late 1980s, such as measuring niche (both realized and fundamental) and assessing possible impacts of climate change, are still highly relevant to key conservation biogeography issues.
Research addressing the effects of habitat fragmentation on species, assemblages or ecosystems has been fraught with difficulties, from its conceptual foundation to statistical analyses and interpretation. Yet, it is critical to address such challenges as ecosystems are rapidly being altered across the world.
Many studies have concluded that effects of habitat loss exceed those of fragmentation per se, that is, the degree to which a given amount of habitat is broken apart. There is also evidence from different biomes and taxa that habitat configuration, that is, the spatial arrangement of habitat at a given time, may influence several landscape processes such as functional connectivity, edge and matrix effects, and thus population viability.
Instead of focusing attention on the relative influence of either habitat loss or fragmentation, we must identify portions of the gradient in habitat amount where configuration effects are most likely to be observed. Here, we suggest that all species are, to a certain degree, sensitive to landscape change and that, assuming a homogeneous matrix, habitat configuration will have a higher influence on species at intermediate values of habitat amount, where configuration has potentially the greatest variability.
On the basis of empirical studies and simulations, we expect that species that are relatively tolerant to fragmentation of their habitat will exhibit a wider band where amount and configuration interact compared to species less tolerant to fragmentation.
Synthesis and applications. Reducing habitat loss should be a top priority for conservation planners. However, researchers should also investigate the indirect impacts of habitat loss on biodiversity through fragmentation effects. This research aims to identify windows of opportunity where habitat configuration can mitigate to some extent the effects of habitat loss, particularly through the maintenance of functional connectivity.
by onlinepublishing@allenpress.com (Michelle D Staudinger et al)
Frontiers in Ecology and the Environment, Volume 11, Issue 9, Page 465-473, November 2013.
This paper provides a synthesis of the recent literature describing how global biodiversity is being affected by climate change and is projected to respond in the future. Current studies reinforce earlier findings of major climate-change-related impacts on biological systems and document new, more subtle after-effects. For example, many species are shifting their distributions and phenologies at faster rates than were recorded just a few years ago; however, responses are not uniform across species. Shifts have been idiosyncratic and in some cases counterintuitive, promoting new community compositions and altering biotic interactions. Although genetic diversity enhances species' potential to respond to variable conditions, climate change may outpace intrinsic adaptive capacities and increase the relative vulnerabilities of many organisms. Developing effective adaptation strategies for biodiversity conservation will not only require flexible decision-making and management approaches that account for uncertainties in climate projections and ecological responses but will also necessitate coordinated monitoring efforts.
