7 research outputs found
Species life‐history strategies affect population responses to temperature and land‐cover changes
Human-induced environmental changes have a direct impact on species populations, with some species experiencing declines while others display population growth. Understanding why and how species populations respond differently to environmental changes is fundamental to mitigate and predict future biodiversity changes. Theoretically, species life-history strategies are key determinants shaping the response of populations to environmental impacts. Despite this, the association between species life histories and the response of populations to environmental changes has not been tested. In this study, we analysed the effects of recent land-cover and temperature changes on rates of population change of 1,072 populations recorded in the Living Planet Database. We selected populations with at least 5 yearly consecutive records (after imputation of missing population estimates) between 1992 and 2016, and for which we achieved high population imputation accuracy (in the cases where missing values had to be imputed). These populations were distributed across 553 different locations and included 461 terrestrial amniote vertebrate species (273 birds, 137 mammals, and 51 reptiles) with different life-history strategies. We showed that populations of fast-lived species inhabiting areas that have experienced recent expansion of cropland or bare soil present positive populations trends on average, whereas slow-lived species display negative population trends. Although these findings support previous hypotheses that fast-lived species are better adapted to recover their populations after an environmental perturbation, the sensitivity analysis revealed that model outcomes are strongly influenced by the addition or exclusion of populations with extreme rates of change. Therefore, the results should be interpreted with caution. With climate and land-use changes likely to increase in the future, establishing clear links between species characteristics and responses to these threats is fundamental for designing and conducting conservation actions. The results of this study can aid in evaluating population sensitivity, assessing the likely conservation status of species with poor data coverage, and predicting future scenarios of biodiversity change
Linking animal behaviour and tree recruitment: Caching decisions by a scatter-hoarder corvid determine seed fate in a Mediterranean agroforestry system
1. Seed dispersal by scatter-hoarder corvids is key for the establishment of important tree species from the Holarctic region such as the walnut (Juglans regia). However, the factors that drive animal decisions to cache seeds in specific locations and the consequences of these decisions on seed fate are poorly understood. /
2. We experimentally created four distinct, replicated habitat types in a Mediterranean agricultural landscape where the Eurasian magpie (Pica pica) is a common scatter hoarder: soft bare soil; compacted bare soil; compacted soil with a dense herbaceous cover; and soft linear bare soil made up of the irrigation furrows that separated the rest of the treatments. We also experimentally placed visual landmarks (stones, sticks and bunches of dry plants) to test if magpies use them to place seed caches. Walnut dispersal from feeders to the habitats was monitored by radiotracking and camera traps. /
3. A sowing experiment simulating natural caches tested the effect of caching type on seed germination and seedling emergence. Seed mass was controlled for the dispersal and sowing experiments. /
4. Magpies selected the two habitats with soft soil, and avoided the one with compacted soil, to cache nuts. Seed mass did not affect dispersal distance, germination or emergence; however, heavier seeds were cached more often under litter and in the habitat with herbaceous cover, whereas lighter seeds were more often buried in the soft bare soil habitat. Seed burial under soil or litter determined seed fate, as there was virtually no emergence from unburied nuts. There was no evidence of any effect of the visual landmarks. /
5. Synthesis. The consequences of seed caching for seedling early establishment are driven by a fine decision-making process of the disperser. Magpies seemed to ponder the characteristics of the habitat and the seed itself to determine where and how to cache each nut. By doing so, magpies reinforced the quality of seed dispersal effectiveness, as they cached walnuts in locations that enhanced both seed survival and seedling emergence
100 años investigando el mar. El IEO en su centenario (1914-2014).
Se trata de un libro que pretende divulgar a la sociedad las principales investigaciones multidisciplinares llevadas a cabo por el Instituto Español de Oceanografía durante su primer siglo de vida, y dar a conocer la historia del organismo, de su Sede Central y de los nueve centros oceanográficos repartidos por los litorales mediterráneo y atlántico, en la península y archipiélagos.Kongsberg 20
Understanding how terrestrial vertebrate life-history shape responses to climatic seasonality and landscape heterogeneity
Life-history theory posits that species pace of life can be described based on species life-history traits: fast species, which have short lifespans and produce numerous offspring; and slow species, which have long lifespans but fewer offspring. A continuum of life-history strategies can be defined between these two extremes. Theoretically, these life-history strategies will give species competitive advantages under different environmental conditions. Fast species are expected to be favoured in more variable environments, whereas slow species are expected to thrive in more homogeneous or stable habitats. This hypothesis is deeply rooted in ecology and conservation, but it hasn´t been tested at a global scale. Filling this gap can allow us to better understand how species respond to anthropogenic environmental changes. In this thesis, I explore how life-history strategies and environmental factors influence the distributions, community composition, and population trends of terrestrial vertebrate species. In Chapter 3, I found that life-history strategies influence the probability of occurrence of species under different conditions of climatic seasonality and landscape heterogeneity. Extending my focus to whole species communities, I found that communities under human-impacted land uses, and climatically seasonal environments have species spanning a wider range of life-history types (life-history richness) and are dominated by fast species (Chapter 4). In my final experimental chapter, I investigated how populations of species with different life-history strategies change due to land-cover and climate warming. Here I show how fast species have benefited from recent land-cover conversions, while slow-lived species’ populations have declined (Chapter 5). Combined, these results show how species life-history influence key species responses to natural gradients and environmental change, and which are the implications of these responses to the conservation of biodiversity. Individually, each experiment shows how the study of interactions between biodiversity and environmental conditions can benefit from the inclusion of species traits
Limited ecophysiological variation in the Canary Island lizard Gallotia galloti (Oudart, 1839) across an elevational range of over 3500 m (Squamata: Lacertidae)
The lacertid lizard Gallotia galloti inhabits drastically different environments on the island of Tenerife, from sea level to > 3500 m, encompassing mesic as well as extremely arid sites. To obtain a first exploratory overview of the thermophysiology of lizards in this range of environments, we experimentally inferred preferred temperature (Tpref) and instant evaporative water loss (IWL) in 63 individuals from five bioclimatically distinct sites. We found statistically significant but weak differences between individual median Tpref values across sites, without an obvious relationship to bioclimate. Considering only adult male lizards, the highest Tpref values were found at one mesic and one very arid site. IWL differences were also significantly different across sites, and this variable was positively correlated with rainfall if analysed at the level of individual lizards, a hypothesis that requires testing against more extensive data sets. It appears that G. galloti occupies an extensive range of bioclimates without heavily adjusting its thermal physiology to local conditions.We are grateful to Juan Antonio Hernández-Agüero for his help collecting lizards in the field, to Johannes Müller who co-initiated a research programme on lacertid lizards, and to Miguel A. Carretero, Rodrigo Megía Palma, and Ariel Rodríguez for fruitful discussions. This study was supported by the Deutsche Forschungsgemeinschaft (grant VE 247/11-1 / MU 1760/9-1). The manuscript was edited by Guido Jones, currently funded by the Cabildo de Tenerife, under the TFinnova Programme supported by MEDI and FDCAN funds. We are grateful to the Cabildo de Tenerife for research and collection permits (AFF 160/18) and to the Landesamt für Verbraucherschutz und Lebensmittelsicherheit in Lower Saxony, Germany for ethics approval of experimentation (Az. 33.19-42502-04-15/1900).Peer reviewe
Environmental temperatures shape thermal physiology as well as diversification and genome-wide substitution rates in lizards
International audienceClimatic conditions changing over time and space shape the evolution of organisms at multiple levels, including temperate lizards in the family Lacertidae. Here we reconstruct a dated phylogenetic tree of 262 lacertid species based on a supermatrix relying on novel phylogenomic datasets and fossil calibrations. Diversification of lacertids was accompanied by an increasing disparity among occupied bioclimatic niches, especially in the last 10 Ma, during a period of progressive global cooling. Temperate species also underwent a genome-wide slowdown in molecular substitution rates compared to tropical and desert-adapted lacertids. Evaporative water loss and preferred temperature are correlated with bioclimatic parameters, indicating physiological adaptations to climate. Tropical, but also some populations of cool-adapted species experience maximum temperatures close to their preferred temperatures. We hypothesize these species-specific physiological preferences may constitute a handicap to prevail under rapid global warming, and contribute to explaining local lizard extinctions in cool and humid climates
100 años investigando el mar. El IEO en su centenario (1914-2014).
Se trata de un libro que pretende divulgar a la sociedad las principales investigaciones multidisciplinares llevadas a cabo por el Instituto Español de Oceanografía durante su primer siglo de vida, y dar a conocer la historia del organismo, de su Sede Central y de los nueve centros oceanográficos repartidos por los litorales mediterráneo y atlántico, en la península y archipiélagos.Kongsberg 200Postprin