Rxivist logo

Rxivist combines preprints from bioRxiv with data from Twitter to help you find the papers being discussed in your field. Currently indexing 83,751 bioRxiv papers from 360,722 authors.

Most downloaded bioRxiv papers, all time

in category ecology

3,586 results found. For more information, click each entry to expand.

2621: Extinction times in diffusive public good population dynamics
more details view paper

Posted to bioRxiv 23 Sep 2018

Extinction times in diffusive public good population dynamics
177 downloads ecology

Gregory J. Kimmel, Philip Gerlee, Philipp M. Altrock

The co-evolutionary dynamics of competing populations can be strongly affected by frequency-dependent selection and population structure in space. As co-evolving populations grow into a spatial domain, their initial spatial arrangement, as well as their growth rate differences determine the dynamics. Here, we are interested in the dynamics of producers and free-rider co-evolution in the context of an ecological public good that is produced by a sub-population but evokes growth benefits to all individuals. We consider the spatial growth dynamics in one, two and three dimensions by modeling producer cell, free-rider cell and public good densities in space, driven by birth, death and diffusion. Typically, one population goes extinct. We find that uncorrelated initial spatial structures do not influence the time to extinction in comparison to the well-mixed system. We derive a slow manifold solution in order to estimate the time to extinction of either free-riders or producers. For invading populations, i.e.~for populations that are initially highly segregated, we observe a traveling wave, whose speed can be calculated to improve the extinction time estimate by a simple superposition of the two times. Our results show that local effects of spatial dynamics evolve independently of the dynamics of the mean populations. Our considerations provide quantitative predictions for the transient dynamics of cooperative traits under pressure of extinction, and a potential experiment to derive elusive details of the fitness function of an ecological public goods game through extinction time observations.

2622: Vegetation and seed bank dynamics highlight the importance of post-restoration management in sown grasslands
more details view paper

Posted to bioRxiv 21 Jan 2020

Vegetation and seed bank dynamics highlight the importance of post-restoration management in sown grasslands
177 downloads ecology

Valko Orsolya, Balazs Deak, Péter Török, Katalin Tóth, Réka Kiss, András Kelemen, Tamás Miglécz, Judit Sonkoly, Béla Tóthmérész

Sowing grass seeds generally supports the rapid development of a closed perennial vegetation, which makes the method universally suitable for fast and effective landscape-scale restoration of grasslands. However, sustaining the recovered grasslands, and increasing their diversity is a challenging task. Understanding the role of seed bank compositional changes and vegetation dynamics contributes to designating management regimes that support the establishment of target species and suppress weeds. Our aim was to reveal the effect of post-restoration management on the vegetation and seed bank dynamics in grasslands restored in one of the largest European landscape-scale restoration projects. Eight years after restoration we sampled the vegetation and seed bank in a total of 96 plots located in 12 recovered grasslands in the Great Hungarian Plain. In each recovered grassland stand we designated a mown (mown from Year 1 to Year 8) and an abandoned sample site (mown from Year 1 to Year 3 then abandoned from Year 4 to Year 8). Mown and abandoned sites showed divergent vegetation and seed bank development. Abandonment led to the decline of sown grasses and higher cover of weeds, especially in the alkaline grasslands. Our study confirmed that seed bank has a limited contribution to the maintenance of biodiversity in both grassland types. We found that five years of abandonment had a larger effect on the seed bank than on the vegetation. We stress that long-term management is crucial for controlling the emergence of the weeds from their dense seed bank in restored grasslands.

2623: Inter- and intra-specific variation of spider mite susceptibility to fungal infections: implications for the long-term success of biological control
more details view paper

Posted to bioRxiv 23 Apr 2019

Inter- and intra-specific variation of spider mite susceptibility to fungal infections: implications for the long-term success of biological control
177 downloads ecology

Flore Zélé, Inês Santos, Ibrahim Cakmak, Sara Magalhães

Spider mites are severe pests of several annual and perennial crops worldwide, often causing important economic damages. Moreover, rapid evolution of pesticide resistance in this group hampers the efficiency of chemical control. Alternative control strategies, such as the use of entomopathogenic fungi, are thus being developed. However, while several studies have focussed on the evaluation of the control potential of different fungal species and/or isolates as well as their compatibility with other control methods (e.g. predators or chemical pesticides), knowledge on the extent of inter- and intraspecific variation in spider mite susceptibility to fungal infection is as yet incipient. Here, we measured the mortality induced by two generalist fungi, Beauveria bassiana and Metarhizium brunneum, in 12 spider mite populations belonging to different Tetranychus species: T. evansi, T. ludeni, the green form of T. urticae and the red form of T. urticae, within a full factorial experiment. We found that spider mite species differed in their susceptibility to infection to both fungal species. Moreover, we also found important intraspecific variation for this trait. These results draw caution on the development of single strains as biocontrol agents. Indeed, the high level of intraspecific variation suggests that (a) the one-size-fits-all strategy will probably fail to control spider-mite populations and (b) hosts resistance to infection may evolve at a rapid pace. Finally, we propose future directions to better understand this system and improve the long-term success of spider mite control strategies based on entomopathogenic fungi.

2624: Seasonality controls the predictive skills of diatom based salinity transfer functions
more details view paper

Posted to bioRxiv 07 Jun 2018

Seasonality controls the predictive skills of diatom based salinity transfer functions
177 downloads ecology

Alejandra Goldenberg Vilar, Timme Donders, Aleksandra Cvetkoska, Friederike Wagner-Cremer

The value of diatoms as bioindicators of contemporary and palaeolimnological studies through transfer function development has increased in the last decades. While they represent a tremendous advance in (palaeo) ecology, these models also leave behind important sources of uncertainties that are often ignored. In the present study we tackle two of the most important sources of uncertainty in the development of diatom salinity inference models: the effect of secondary variables associated to seasonality and the comparison of conventional cross-validation methods with a validation based on independent datasets. Samples (diatoms and environmental variables) were taken in spring, summer and autumn in the freshwater and brackish ditches of the province of North Holland in 1993 and sampled again different locations of the same province in 2008-2010 to validate the models. We found that the abundance of the dominant species significantly changed between the seasons, leading to inconsistent estimates of species optima and tolerances. A model covering intra-annual variability (all seasons combined) provides averages of species optima and tolerances, reduces the effect of secondary variables due to the seasonality effects, thus providing the strongest relationship between salinity and diatom species. In addition, the "all-season" model also reduces the edge effects usually found in all unimodal-based calibration methods. While based on cross-validation all four models seem to perform relatively well, a validation with an independent dataset emphasizes the importance of using models covering intra-annual variability to perform realistic reconstructions.

2625: Deciphering the many maps of the Xingu, an assessment of deforestation from land cover classifications at multiple scales
more details view paper

Posted to bioRxiv 27 Dec 2019

Deciphering the many maps of the Xingu, an assessment of deforestation from land cover classifications at multiple scales
177 downloads ecology

M Kalacska, J.P Arroyo-Mora, O. Lucanus, L Sousa, T Pereira, T Vieira

Remote sensing is an invaluable tool to objectively illustrate the rapid decline in habitat extents worldwide. Over the years, diverse Earth Observation platforms have been used to generate land cover maps, each with its unique characteristics. In addition, considerable semantic differences between the definition of land cover classes results in inevitable differences in baseline estimates for each class (e.g. forest). Here we compare forest cover and surface water estimates over four time periods spanning three decades for the Xingu River basin, Brazil, from pre-existing remotely sensed classifications for this area based on both optical and radar data. Because forest health in this area is directly related with the health of the freshwater ecosystem, we illustrate potential impacts of map choice on conservation of fish fauna. Understanding differences between the many remotely sensed baselines is fundamentally important to avoid information misuse and objectively decide on the most appropriate dataset for each conservation or policy making question. Our findings demonstrate the importance of transparency in the generation of remotely sensed datasets and in the importance of users familiarizing themselves with the characteristics and limitations of each data set chosen.

2626: Worldwide recombination in emergent white-nose syndrome pathogen Pseudogymnoascus destructans
more details view paper

Posted to bioRxiv 08 Dec 2019

Worldwide recombination in emergent white-nose syndrome pathogen Pseudogymnoascus destructans
177 downloads ecology

Lav Sharma, Márcia Sousa, Ana S. Faria, Margarida Nunes-Pereira, João A. Cabral, Alan J. L. Phillips, Guilhermina Marques, Maria das Neves Paiva-Cardoso

Pseudogymnoascus destructans (Pd), the emergent fungus causing bat White-Nose Syndrome, responsible for ~6 million mortalities in the United States (US), is thought to expand clonally in North America and Europe. Presence of distinct mating-types in Europe led to numerous research attempts searching for population sexuality worldwide. This study not only presents the first evidence of genetic recombination in Pd but also detects recombination in Pd genotype data generated by previous studies in Europe and North America, through clone-corrected linkage disequilibrium analysis. Portuguese and other European populations are apparently reproducing through sex between two mating-types. Seeming parasexual recombination in the invasive single mating-type US population rings alarms for the North American bat populations and deserves urgent attention. This study emphasizes on clone-correction in linkage disequilibrium analysis.

2627: Will the Illinois chorus frog (Pseudacris streckeri illinoensis) survive in Arkansas? A case study of a secretive species in need of protection
more details view paper

Posted to bioRxiv 12 Jun 2018

Will the Illinois chorus frog (Pseudacris streckeri illinoensis) survive in Arkansas? A case study of a secretive species in need of protection
177 downloads ecology

Malcolm McCallum, Stanley E Trauth

The range of the Illinois chorus frog (Pseudacris streckeri illinoensis) in Arkansas is restricted to the eastern quarter of Clay County. Nearly 100% of this species' native sand-prairie habitat has been converted to agricultural fields. The original range of the Illinois chorus frog encompassed at least 9,982 ha. Although two new localities were identified in 2002, the current range is only 4,399 ha in 2002. This represents a 56% range contraction since 1992. Calling was heard in only 44.5% of its original range. This species may be experiencing a severe range contraction. Decay models predict the extirpation of the Illinois chorus frog in Arkansas within 17.5 to 101 yr. Suggested factors contributing to this range contraction may include drought, pesticide use, changes in surface water hydrology, U.S. E.P.A. Best management practices, and this species' limited ability to recolonize extirpated sites.

2628: Applying Machine Learning to Investigate Long Term Insect-Plant Interactions Preserved on Digitized Herbarium Specimens
more details view paper

Posted to bioRxiv 02 Oct 2019

Applying Machine Learning to Investigate Long Term Insect-Plant Interactions Preserved on Digitized Herbarium Specimens
177 downloads ecology

Emily K. Meineke, C. Tomasi, S. Yuan, K.M. Pryer

Premise of the study: Despite the economic importance of insect damage to plants, long-term data documenting changes in insect damage (herbivory) and diversity are limited. Millions of pressed plant specimens are now available online for collecting big data on plant-insect interactions during the Anthropocene. Methods: We initiated development of machine learning methods to automate extraction of herbivory data from herbarium specimens. We trained an insect damage detector and a damage type classifier on two distantly related plant species. We experimented with 1) classifying six types of herbivory and two control categories of undamaged leaf, and 2) detecting two of these damage categories for which several hundred annotations were available. Results: Classification models identified the correct type of herbivory 81.5% of the time. The damage classifier was accurate for categories with at least one hundred test samples. We show anecdotally that the detector works well when asked to detect two types of damage. Discussion: The classifier and detector together are a promising first step for the automation of herbivory data collection. We describe ongoing efforts to increase the accuracy of these models to allow other researchers to extract similar data and apply them to address a variety of biological hypotheses.

2629: Parasite transmission in aquatic ecosystems under climate change: joint effects of temperature, host behavior and elimination of parasite larvae by predators.
more details view paper

Posted to bioRxiv 14 Sep 2019

Parasite transmission in aquatic ecosystems under climate change: joint effects of temperature, host behavior and elimination of parasite larvae by predators.
177 downloads ecology

M. Gopko, E. Mironova, A. Pasternak, V. Mikheev, J. Taskinen

A moderate raise in temperature was suggested to enhance the impact of parasites on aquatic ecosystems. Under higher temperatures, poikilothermic animals (e.g. fish), increase their activity, which can result in a more frequent encounter with parasites. However, temperature increase may also trigger processes counteracting an increased risk of parasitic infections. For instance, removal of free-living stages of parasites by filter-feeding organisms can increase with temperature and potentially mitigate disease risk in ecosystems under climate change. In our study, we aimed to find out whether an increased infection transmission under higher temperatures can be, at least, partly compensated by the increased removal of parasitic larvae be aquatic predators. In addition, we planned to reveal the behavioral mechanism underlying the more successful transmission of the parasite at higher temperatures. We experimentally studied how temperature, the behavior of fish host (rainbow trout) and the presence of filter-feeding mussels in the environment influence transmission success of trematode larvae (Diplostomum pseudospathaceum cercariae) to fish host. We found that temperature raise increased, while presence of filter-feeding mussels in the environment decreased infection intensities in fish. However, the effect of mussel presence was constant within the tested range of water temperatures (15-23C), which suggests that it cannot compensate for the observed increased transmission of parasites under temperature raise. The difference in fish individual behavior (swimming activity) before the exposure to parasites was a substantial factor the affecting host vulnerability to infection. However, fish motor activity only weakly correlated with temperature, therefore, it is unlikely to be responsible for the increased infection success under warmer conditions. After exposure to parasites, fish strongly decreased their activity. This decrease was temperature-dependent and more pronounced in bolder (more active) fish, which leads to lower variability in activity of fish exposed to parasites compared with the safe environment. Post-exposure activity did not influence the infection intensity. In general, we showed that the elimination of trematode larvae by filter-feeders is unlikely to deter the potential effects of global warming on host-parasite interactions in temperate freshwater ecosystems.

2630: Low marine food levels mitigate high migration costs in anadromous populations
more details view paper

Posted to bioRxiv 14 Mar 2019

Low marine food levels mitigate high migration costs in anadromous populations
176 downloads ecology

P. Catalina Chaparro-Pedraza, André M. de Roos

Migratory fish populations, like salmon, have dramatically declined for decades. Because of their extensive and energetically costly breeding travel anadromous fish are sensitive to a variety of environmental threats, in particular infrastructure building in freshwater streams and food declines in the ocean. Here, we analyze the effects of these two threats combined. Unexpectedly, we find that low marine food availabilities favor, as opposed to threaten, the ecological success of endangered populations. This counterintuitive effect results from an aspect of individual energetics that individuals switching to higher food levels reach larger sizes with concomitant larger migration costs but have lower energy densities. Surprisingly, the decline of food levels in the ocean after the completion of dams may thus mitigate the risk of extinction of migratory fish populations. This highlights the need of a mechanistic understanding integrating individual energetics, life history, and population dynamics to accurately assess biological consequences of environmental change.

2631: A framework for quantifying deviations from dynamic equilibrium theory
more details view paper

Posted to bioRxiv 05 Sep 2019

A framework for quantifying deviations from dynamic equilibrium theory
176 downloads ecology

Michael Kalyuzhny, Curtis H. Flather, Nadav M. Shnerb, Ronen Kadmon

Community assembly is governed by colonization and extinction processes, and the simplest model describing it is Dynamic Equilibrium (DE) theory, which assumes that communities are shaped solely by stochastic colonization and extinction events. Despite its potential to serve as a null model for community dynamics, there is currently no accepted methodology for measuring deviations from the theory and testing it. Here we propose a novel and easily applicable methodology for quantifying deviations from the predictions and assumptions of DE by comparing observed community time-series to a randomization-based null model. We show that this methodology has good statistical properties on simulated data, and it can detect deviations from both the assumptions and predictions of DE in the classical Florida Keys experiment. We discuss alternative methods and present guidelines for practical use of the methodology, hoping it will enhance the applicability of DE as a reference for studying changes in ecological communities.

2632: Wolbachia affect behavior and possibly reproductive compatibility but not thermoresistance, fecundity, and morphology in a novel transinfected host, Drosophila nigrosparsa
more details view paper

Posted to bioRxiv 22 Jan 2020

Wolbachia affect behavior and possibly reproductive compatibility but not thermoresistance, fecundity, and morphology in a novel transinfected host, Drosophila nigrosparsa
176 downloads ecology

Matsapume Detcharoen, Wolfgang Arthofer, Francis M. Jiggins, Florian M. Steiner, Birgit C. Schlick-Steiner

Wolbachia , intracellular endosymbionts, are estimated to infect about half of all arthropod species. These bacteria manipulate their hosts in various ways for their maximum benefits. The rising global temperature may accelerate species migration and, thus, horizontal transfer of Wolbachia may occur across species previously not in contact. We transinfected and then cured the alpine fly Drosophila nigrosparsa with Wolbachia strain wMel to study its effects on this species. We found low Wolbachia titer, possibly cytoplasmic incompatibility, and an increase in locomotion of both infected larvae and adults compared with cured ones. However, no change in fecundity, no impact on heat and cold tolerance, and no change in wing morphology were observed. Although Wolbachia increased locomotor activities in this species, we conclude that D. nigrosparsa may not benefit from the infection. Still, D. nigrosparsa can serve as a host for Wolbachia because vertical transmission is possible but may not be as high as in the native host of wMel, Drosophila melanogaster .

2633: Factors affecting the biology of Pachycrepoideus vindemmiae (Hymenoptera: Pteromalidae) on spotted-wing drosophila (Drosophila suzukii)
more details view paper

Posted to bioRxiv 31 May 2019

Factors affecting the biology of Pachycrepoideus vindemmiae (Hymenoptera: Pteromalidae) on spotted-wing drosophila (Drosophila suzukii)
176 downloads ecology

Cherre S. Bezerra Da Silva, Briana E. Price, Alexander Soohoo-Hui, Vaughn M. Walton

Pachycrepoideus vindemmiae is a parasitoid of the invasive spotted-wing drosophila (SWD, Drosophila suzukii) in the U.S. Few studies have addressed interactions between these two species and little is known about the potential of this parasitoid as a biocontrol agent of SWD. Here, we investigated the impact of extrinsic and intrinsic factors on life-history traits of P. vindemmiae. Both constant (entire adulthood) and limited (30 minutes) supply of water + honey, honey, or host increased parasitoid survival compared to controls (water or fasting). Water + honey caused the highest parasitoid survivals (35-60 days), independent of supply period, sex, and host availability. Females were intrinsically more resistant to water and honey scarcity than males, and host-feeding elevated such resistance even higher. Constant supply of honey supported the highest host-killing capacity (ca. 600 SWD pupae/wasp). However, in young females (4-9 days old), such honey effect was insignificant while water deprivation (either with or without honey) resulted in the highest host-killing potential. This indicate that although sugar becomes a critical nutritional resource as females age, young females depend more on water than sugar. No effect of water nor honey was observed on the sex ratio of young females, but when we considered the entire adulthood honey supply produced the lowest proportion of females (0.50), independent of water availability. Such reduction derived from sperm depletion, likely caused by both lack of re-mating and higher fecundity in honey-fed wasps. Neither water nor honey affected parasitoid emergence rate (0.97), independent of female age. Based on survival and host-killing capacity, we conclude that P. vindemmiae has a tremendous biocontrol potential against SWD. Both limited and constant supply of water, sugar, and host increase parasitoid survival, while constant supply of water and/or honey enhance its host-killing potential and decrease sex ratio depending on mother age.

2634: nosoi: a stochastic agent-based transmission chain simulation framework in R
more details view paper

Posted to bioRxiv 04 Mar 2020

nosoi: a stochastic agent-based transmission chain simulation framework in R
176 downloads ecology

Sébastian Lequime, Paul Bastide, Simon Dellicour, Philippe Lemey, Guy Baele

The transmission process of an infectious agent creates a connected chain of hosts linked by transmission events, known as a transmission chain. Reconstructing transmission chains remains a challenging endeavor, except in rare cases characterized by intense surveillance and epidemiological inquiry. Inference frameworks attempt to estimate or approximate these transmission chains but the accuracy and validity of such methods generally lack formal assessment on datasets for which the actual transmission chain was observed. We here introduce nosoi, an open-source R package that offers a complete, tunable, and expandable agent-based framework to simulate transmission chains under a wide range of epidemiological scenarios for single-host and dual-host epidemics. nosoi is accessible through GitHub and CRAN, and is accompanied by extensive documentation, providing help and practical examples to assist users in setting up their own simulations. Once infected, each host or agent can undergo a series of events during each time step, such as moving (between locations) or transmitting the infection, all of these being driven by user-specified rules or data, such as travel patterns between locations. nosoi is able to generate a multitude of epidemic scenarios, that can - for example - be used to validate a wide range of reconstruction methods, including epidemic modeling and phylodynamic analyses. nosoi also offers a comprehensive framework to leverage empirically acquired data, allowing the user to explore how variations in parameters can affect epidemic potential. Aside from research questions, nosoi can provide lecturers with a complete teaching tool to offer students a hands-on exploration of the dynamics of epidemiological processes and the factors that impact it. Because the package does not rely on mathematical formalism but uses a more intuitive algorithmic approach, even extensive changes of the entire model can be easily and quickly implemented.

2635: Integration of system phenotypes in microbiome networks to identify candidate synthetic communities: a study of the grafted tomato rhizobiome
more details view paper

Posted to bioRxiv 13 Dec 2019

Integration of system phenotypes in microbiome networks to identify candidate synthetic communities: a study of the grafted tomato rhizobiome
176 downloads ecology

Ravin Poudel, Ari Jumpponen, Megan Kennelly, Cary Rivard, Lorena Gomez-Montano, K. A. Garrett

Understanding factors influencing microbial interactions, and designing methods to identify key taxa, are complex challenges for achieving microbiome-based agriculture. Here we use a grafted tomato system to study how grafting and the choice of rootstock influence root-associated fungal communities. We then construct a phenotype-OTU network analysis (PhONA) using random forest and network models of the observed sequence-based fungal Operational Taxonomic Units (OTUs) and associated tomato yield data. PhONA provides a framework to select a testable and manageable number of OTUs to support microbiome-based agriculture. We studied three tomato rootstocks (BHN589, RST-04-106 and Maxifort) grafted to a BHN589 scion and profiled the associated endosphere and rhizosphere fungal communities by sequencing the fungal Internal Transcribed Spacer (ITS2). The data provided evidence for a rootstock effect (explaining ~2% of the total captured variation, p < 0.01) on the fungal community. Moreover, the most productive rootstock, Maxifort, supported higher fungal species richness than the other rootstocks or controls. Differentially abundant OTUs (DAOTUs) specific to each rootstock were identified for both endosphere and rhizosphere compartments. PhONA integrates the information about individual OTU obtained via differential abundance tests and role analyses. It identified OTUs that were directly important for predicting tomato yield, and other OTUs that were indirectly linked to yield through their links to these OTUs. Fungal OTUs that are directly or indirectly linked with tomato yield represent candidate components of synthetic communities for testing in agricultural systems.

2636: Rare species perform worse than common species under changed climate
more details view paper

Posted to bioRxiv 16 Oct 2019

Rare species perform worse than common species under changed climate
176 downloads ecology

Hugo Vincent, Christophe N. Bornand, Anne Kempel, Markus Fischer

Predicting how species, particularly rare and endangered ones, will react to climate change is a major current challenge in ecology. Rare species are expected to have a narrower niche width than common species. However, we know little whether they are also less able to cope with new climatic conditions. To simulate climate change, we transplanted 35 plant species varying in rarity to five botanical gardens in Switzerland, differing in altitude. For each species we calculated the difference in climate between their natural habitats and the novel climate of the respective botanical garden. We found that rare species had generally lower survival and biomass production than common species. Moreover, rare plant species survived less when the amount of precipitation differed more from the one in their natural range, indicating a higher susceptibility to climate change. Common species, in contrast, survived equally well under all climates and even increased their biomass under wetter or drier conditions. Our study shows that rarer species are less able to cope with changes in climate compared to more widespread ones, which might even benefit from these changes. This indicates that already rare and endangered plant species might suffer strongly from future climate change.

2637: Would conserving natural land cover in landscapes conserve biodiversity?
more details view paper

Posted to bioRxiv 05 Oct 2018

Would conserving natural land cover in landscapes conserve biodiversity?
176 downloads ecology

Rafael X. De Camargo, David J. Currie

It is generally accepted that protecting natural land cover would protect biodiversity. This would only be true as a general statement if the relationship between richness and natural land cover were monotonic positive and scale- and method-independent. Assertions about habitat loss causing species losses often come from broad-scale assessment of richness (e.g., from range maps) combined with patterns of natural habitat conversion. Yet, the evidence about species loss following habitat loss or fragmentation typically comes from fine-scale experiments. Here, we test whether broad-extent relationships between avian species richness and natural land cover are independent of: 1) whether species distribution data come from systematic censuses (atlases) versus range maps, and 2) the grain size of the analysis. We regressed census-based and range map-based avian species richness against the proportion of natural land cover and temperature. Censused richness at the landscape level was obtained from Breeding Bird Atlases of Ontario and New York State. Range-map richness derived from BirdLife International range maps. Comparisons were made across different spatial grains: 25-km2, 100-km2, and 900-km2. Over regional extents, range-map richness relates strongly to temperature, irrespective of spatial grain. Censused species richness relates to temperature less strongly. Range-map richness is a negative function of the proportion of natural land cover, while realized richness is a peaked function. The two measures of richness are not monotonically related to each other. In conclusion, the data do not indicate that, in practice, landscapes with greater natural land cover in southern Ontario or in New York State have higher species richness. Moreover, different data types can lead to dramatically different relationships between richness and natural land cover. We argue that the argument that habitat loss is the main driver of species loss has become a panchreston. It may be misguiding conservation biology strategies by focusing on a threat that is too general to be usefully predictive.

2638: Pre-adaptation to climate change through topography-driven evolution of traits and their plasticity
more details view paper

Posted to bioRxiv 29 Oct 2019

Pre-adaptation to climate change through topography-driven evolution of traits and their plasticity
176 downloads ecology

H. De Kort, B. Panis, S.B. Janssens, K. Helsen, O. Honnay

Climate change is expected to increase the level of drought stress experienced by many plant populations, yet the spatial distribution of changes in dryness remains highly uncertain. Species can, to some extent, adapt to climate uncertainty through evolving increased trait plasticity. Biodiversity conservation could capitalize on such natural variation in the ability of populations to cope with climate variability. Yet, disentangling evolution of trait means vs. trait plasticity is challenging, as it requires a sampling design with genetic replicates grown under distinct environmental conditions. Here, we applied different soil moisture treatments to clones of Fragaria vesca plants that were raised from seeds that were sampled in distinct mountainous topographical settings, to study adaptive trait and plasticity divergence in response to drought. We demonstrate that various fitness traits evolved along topographical gradients, including increased specific leaf area (SLA) with increasing slope, and increased growth plasticity with increasing altitude. Our results indicate that traits and their plasticity can evolve independently in response to distinct topographical stressors. We further show that trait heritability varies considerably among traits and topographical settings. Heritability of phenotypic plasticity tended to increase with altitude for all traits, with populations from high altitudes harboring more than twice the heritability for growth and SLA plasticity compared to populations from low altitudes. We conclude that (i) low altitudinal populations, which are expected to be least vulnerable to climate change, may only withstand limited increases in drought stress, while (ii) populations that evolved to thrive under more heterogeneous mountain conditions are pre-adapted to climate change through high plasticity and heritability. Highly heterogeneous landscapes may thus represent invaluable sources of quantitative genetic variation that could support conservation under climate change across the globe.

2639: Born to run? Quantifying the balance of prior bias and new information in prey escape decisions
more details view paper

Posted to bioRxiv 07 Apr 2018

Born to run? Quantifying the balance of prior bias and new information in prey escape decisions
176 downloads ecology

Nicholas M. Sutton, James P. O’Dwyer

Animal behaviors can often be challenging to model and predict, though optimality theory has improved our ability to do so. While many qualitative predictions of behavior exist, accurate quantitative models, tested by empirical data, are often lacking. This is likely due to variation in biases across individuals and variation in the way new information is gathered and used. We propose a modeling framework based on a novel interpretation of Bayes' theorem to integrate optimization of energetic constraints with both prior biases and specific sources of new information gathered by individuals. We present methods for inferring distributions of prior biases within populations rather than assuming known priors, as is common in Bayesian approaches to modelling behavior, and for evaluating the goodness of fit of overall model descriptions. We apply this framework to predict optimal escape during predator-prey encounters, based on prior biases and variation in what information prey use. Using this approach we collected and analyzed data characterizing white-tailed deer (Odocoileus virginianus) escape behavior in response to human approaches. We found that distance to predator alone was not sufficient for predicting deer flight response, and have shown that the inclusion of additional information is necessary. Additionally, we compared differences in the inferred distributions of prior biases across different populations and discuss the possible role of human activity in influencing these distributions.

2640: Edge fires drive the shape and stability of tropical forests
more details view paper

Posted to bioRxiv 14 Feb 2018

Edge fires drive the shape and stability of tropical forests
176 downloads ecology

Laurent Hébert-Dufresne, Adam F. A. Pellegrini, Uttam Bhat, Sidney Redner, Stephen W. Pacala, Andrew M. Berdahl

In tropical regions, fires propagate readily in grasslands but typically consume only edges of forest patches. Thus forest patches grow due to tree propagation and shrink by fires in surrounding grasslands. The interplay between these competing edge effects is unknown, but critical in determining the shape and stability of individual forest patches, as well the landscape-level spatial distribution and stability of forests. We analyze high-resolution remote-sensing data from protected areas of the Brazilian Cerrado and find that forest shapes obey a robust perimeter-area scaling relation across climatic zones. We explain this scaling by introducing a heterogeneous fire propagation model for tropical forest-grassland ecotones. Deviations from this perimeter-area relation determine the stability of individual forest patches. At a larger scale, our model predicts that the relative rates of tree growth due to propagative expansion and long-distance seed dispersal determine whether collapse of regional-scale tree cover is continuous or discontinuous as fire frequency changes.

Previous page 1 . . . 130 131 132 133 134 135 136 . . . 180 Next page

PanLingua

Sign up for the Rxivist weekly newsletter! (Click here for more details.)


News