New publications from our team - 19 JAN 2019
The main paper of PhD thesis of K. Sam was published online in Journal of Biogeography
Sam K, Koane B, Bardos DC, Jeppy S, Novotny V. Species richness of birds along a complete rain forest elevational gradient in the tropics: Habitat complexity and food resources matter. J Biogeogr. 2019;00:1–12. https://doi.org/10.1111/jbi.13482
K.Sam contributed samples and participated on publication about microbiota of New Guinean birds.
Bodawatta, K. H., Sam, K., Jønsson, K. A., & Poulsen, M. (2018). Comparative analyses of the digestive tract microbiota of New Guinean passerine birds. Frontiers in microbiology, 9, 1830.
K.Sam participated on a paper about see-syndromes in three trpical forests of the world:
Dahl, C., Ctvrtecka, R., Gripenberg, S., Lewis, O. T., Segar, S. T., Klimes, P., ... & Panmeng, M. (2018). The insect-focused classification of fruit syndromes in tropical rainforests: an inter-continental comparison. Biotropica.
Sam K, Koane B, Bardos DC, Jeppy S, Novotny V. Species richness of birds along a complete rain forest elevational gradient in the tropics: Habitat complexity and food resources matter. J Biogeogr. 2019;00:1–12. https://doi.org/10.1111/jbi.13482
K.Sam contributed samples and participated on publication about microbiota of New Guinean birds.
Bodawatta, K. H., Sam, K., Jønsson, K. A., & Poulsen, M. (2018). Comparative analyses of the digestive tract microbiota of New Guinean passerine birds. Frontiers in microbiology, 9, 1830.
K.Sam participated on a paper about see-syndromes in three trpical forests of the world:
Dahl, C., Ctvrtecka, R., Gripenberg, S., Lewis, O. T., Segar, S. T., Klimes, P., ... & Panmeng, M. (2018). The insect-focused classification of fruit syndromes in tropical rainforests: an inter-continental comparison. Biotropica.
BABE Project - Field WoRK in Australia - nov/dec 2018
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Six our team members set the complete replication of BABE project at two study sites in Australia (Sara Fernandez Gomez, Martin Libra, Ondra Mottl in Sydney, at EucFACE and Legi Sam, Marketa Tahadlova, Jan Lenc in Daintree). It took us 6 weeks and some extra days for insect rearing. Katerina Sam was first working with team in Sydney, then flew to check team in Cairns. During her travels, she also visited Canopy Crane opening in Papua New Guinea.
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New publication from our team - 22 Sep 2017
Very first "first-author" paper of my PhD student Anna Mrazova was published online today. The manuscript was part of her Master thesis, and was published just 6 months after her defense. Congratulations to this good start!
Application of methyl jasmonate to grey willow (Salix cinerea) attracts insectivorous birds in nature
Application of methyl jasmonate to grey willow (Salix cinerea) attracts insectivorous birds in nature
Last field work to Podyji NP for this year - 18 Sep 2017
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We visited Anna's study site in Moravia for the last time in this year. While all the saplings will continue growing under our treatments, we will be busy to analyze all collected samples and measurements. We hope to see all saplings alive in April 2018.
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Field work in Czech Republic 2017 - 7 Jun 20017
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This season, we are very active in Czech Republic at several study sites. We already spent one full month in the field, and employed several assistants to help us with the field work.
Anna works on predator exclusion experiment in National Park in Podyji, while Marketa works on succession on several study sites around Ceske Budejovice. Both projects are comparative to the activities just happening in Papua New Guinea, where Legi and Piotr are taking care of the experiments. Anna excluded birds and bats from shrubs and trees of several species, and will focus on changes in insect communities, in chemical and trait responses of the trees. Marketa's project is a long-term experiment, focused on secondary succession under different treatments (predator exclusions, insect inclusion etc.). |
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Media attention gained
The paper I participated on and was published in Science gained some public and press attention. I was country representative and media contact. Here are some links to press articles (in Czech only):
In Ekolist - Česká vědkyně se podílela na unikátním výzkumu. Klíčovou roli hrály housenky z plastelíny
In National Radio (Cesky Rozhlas) - Afternoon guest (Odpoledni host) 21.7.2017
In National Radio (Cesky Rozhlas) - Leonardo 20.7.2017
In Ekolist - Česká vědkyně se podílela na unikátním výzkumu. Klíčovou roli hrály housenky z plastelíny
In National Radio (Cesky Rozhlas) - Afternoon guest (Odpoledni host) 21.7.2017
In National Radio (Cesky Rozhlas) - Leonardo 20.7.2017
Laboratory of Multitrophic Interactions established - 1 Mar 2017
By 1st of March 2017, my Laboratory of Multitrophic Interactions started its existence officially under the Department of Ecology at Institute of Entomology of Biology Centre CAS.
Autumn/winter 2017 - 31 Jan 2017
Writing, writing and writing in progress. Besides my own activities, I am very proud of Anna Humlova, who defended her Master thesis in December, was accepted for Ph.D. studies and developed her project over the winter. Our Bachelor student Adela Kotounova successfully defended her thesis on Functional diversity on Melanesian birds in spring 2017 and left our laboratory.
We attended ATBC conference 2016 in Montpellier - 30 Jun 2016
Here we are posting some photos form our trip to Toulouse to visit Christophe Thebaud and to ATBC in Montpellier. I was giving both oral and poster presentation about my own work and work of my student Anna Humlova. The meeting was really great and enjoyable this year and I can't wait for next year in Mexico.
Field season is on on both continents and we were doing well in last months - 12 Jun 2016
Nearly all my students are back in the field after the exams. Anna is hard working on bird-caterpillar experiments in Czech Republic. Peter and Bulisa are getting ready for difficult field trips starting early next week, and Richard is already 3 months in harsh conditions of Mt. Wilhelm gradient. Only myself and Adela are working from offices, and I will be heading to France for ATBC conference later next week.
During last three months, two of my collaborative papers were published:
Wilson KA, Auerbach NA, Sam K, Magini AG, Moss AS, Langhans SD, Budiharta S, Terzano D, Meijaard E. Conservation Research Is Not Happening Where It Is Most Needed. PLoS Biol. 2016 Mar 29;14(3):e1002413.
Colwell et al. Midpoint attractors and species richness: Modeling the interaction between environmental drivers and geometric constraints. Ecology Letters (in print)
During last three months, two of my collaborative papers were published:
Wilson KA, Auerbach NA, Sam K, Magini AG, Moss AS, Langhans SD, Budiharta S, Terzano D, Meijaard E. Conservation Research Is Not Happening Where It Is Most Needed. PLoS Biol. 2016 Mar 29;14(3):e1002413.
Colwell et al. Midpoint attractors and species richness: Modeling the interaction between environmental drivers and geometric constraints. Ecology Letters (in print)
New publications from our team - 17 Mar 2016
Májeková M, Paal T, Plowman NS, Bryndová M, Kasari L, Norberg A, Weiss M, Bishop TR, Luke SH, Sam K, Le Bagousse-Pinguet Y. Evaluating Functional Diversity: Missing Trait Data and the Importance of Species Abundance Structure and Data Transformation. PloS one. 2016 Feb 16;11(2):e0149270.
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0149270
Sam K, Remmel T, Molleman F. Material affects attack rates on dummy caterpillars in tropical forest where arthropod predators dominate: an experiment using clay and dough dummies with green colourants on various plant species. Entomologia Experimentalis et Applicata. 2015 1;157(3):317-24. (full text upon request)
In communities of tropical insects, adult abundance tends to fluctuate widely, perhaps in part owing to predator–prey dynamics. Yet, temporal patterns of attack rates in tropical forest habitats have not been studied systematically; the identity of predators of insects in tropical forests is poorly known; and their responses to temporal variation in prey abundance have rarely been explored. We recorded incidence and shape of marks of attacks on dummy caterpillars (proxy of predation rate) in a sub-montane tropical forest in Uganda during a yearlong experiment, and explored correlations with inferred caterpillar abundance. Applying the highest and lowest observed daily attack rates on clay dummies over a realistic duration of the larval stage of butterflies, indicates that the temporal variation in attack rate could cause more than 10-fold temporal variation in caterpillar survival. Inferred predatorswere almost exclusively invertebrates, and beak marks of birds were very scarce. Attack rates by wasps varied more over time than those of ants. Attack rates on dummies peaked during the two wet seasons, and appeared congruent with inferred peaks in caterpillar density. This suggests (1) a functional response (predators shifting to more abundant resource) or adaptive timed phenology (predators timing activity or breeding to coincide with seasonal peaks in prey abundance) of predators, rather than a numerical response (predator populations increasing following peaks in prey abundance); and (2) that predation would dampen abundance fluctuations of tropical Lepidoptera communities.
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0149270
Sam K, Remmel T, Molleman F. Material affects attack rates on dummy caterpillars in tropical forest where arthropod predators dominate: an experiment using clay and dough dummies with green colourants on various plant species. Entomologia Experimentalis et Applicata. 2015 1;157(3):317-24. (full text upon request)
In communities of tropical insects, adult abundance tends to fluctuate widely, perhaps in part owing to predator–prey dynamics. Yet, temporal patterns of attack rates in tropical forest habitats have not been studied systematically; the identity of predators of insects in tropical forests is poorly known; and their responses to temporal variation in prey abundance have rarely been explored. We recorded incidence and shape of marks of attacks on dummy caterpillars (proxy of predation rate) in a sub-montane tropical forest in Uganda during a yearlong experiment, and explored correlations with inferred caterpillar abundance. Applying the highest and lowest observed daily attack rates on clay dummies over a realistic duration of the larval stage of butterflies, indicates that the temporal variation in attack rate could cause more than 10-fold temporal variation in caterpillar survival. Inferred predatorswere almost exclusively invertebrates, and beak marks of birds were very scarce. Attack rates by wasps varied more over time than those of ants. Attack rates on dummies peaked during the two wet seasons, and appeared congruent with inferred peaks in caterpillar density. This suggests (1) a functional response (predators shifting to more abundant resource) or adaptive timed phenology (predators timing activity or breeding to coincide with seasonal peaks in prey abundance) of predators, rather than a numerical response (predator populations increasing following peaks in prey abundance); and (2) that predation would dampen abundance fluctuations of tropical Lepidoptera communities.
We attended European Conference of Tropical Ecology - 29 Feb 2016
We were excited to be able to attend "GTO" conference again, this time in Gottingen in Germany. I managed to prepare three presentations - one talk about my exclosure experiments, and a poster about my older work from elevational gradient. The third talk given by me was on behalf of Bo Dalsgaard who was not able to attend. In total, 10 participants from our department had 10 talks and 1 poster. Symposium organized by me and co-chaired by Marcell Peters was so large it had to run for two days.
Below, you can also download my talk and poster, and talk of my student Anna Humlova.
Below, you can also download my talk and poster, and talk of my student Anna Humlova.
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Quick field trip to PNG again! - 22 Feb 2016
In February, I have been teaching ornithological methods to our new colleagues. We were working in Middle Ramu and we really enjoyed lot of mud and fun. It was great fun to work with my assistant Bonny again, after so long time. We worked also with people from Forest Research Institute, who were working on botanical part of the survey.
In the mean time, my student Peter mick was somewhere in Milne Bay to conduct another survey. |
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New publication from our team - 13 Oct 2015
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Molleman, F., Remmel, T., Sam, K. (2015) Phenology of Predation on Insects in a Tropical Forest: Temporal Variation in Attack
Rate on Dummy Caterpillars. Biotropica 10.1111/btp.12268 In communities of tropical insects, adult abundance tends to fluctuate widely, perhaps in part owing to predator–prey dynamics. Yet, temporal patterns of attack rates in tropical forest habitats have not been studied systematically; the identity of predators of insects in tropical forests is poorly known; and their responses to temporal variation in prey abundance have rarely been explored. We recorded incidence and shape of marks of attacks on dummy caterpillars (proxy of predation rate) in a sub-montane tropical forest in Uganda during a yearlong experiment, and explored correlations with inferred caterpillar abundance. Applying the highest and lowest observed daily attack rates on clay dummies over a realistic duration of the larval stage of butterflies, indicates that the temporal variation in attack rate could cause more than 10-fold temporal variation in caterpillar survival. Inferred predators were almost exclusively invertebrates, and beak marks of birds were very scarce. Attack rates by wasps varied more over time than those of ants. Attack rates on dummies peaked during the two wet seasons, and appeared congruent with inferred peaks in caterpillar density. This suggests (1) a functional response (predators shifting to more abundant resource) or adaptive timed phenology (predators timing activity or breeding to coincide with seasonal peaks in prey abundance) of predators, rather than a numerical response (predator populations increasing following peaks in prey abundance); and (2) that predation would dampen abundance fluctuations of tropical Lepidoptera communities. |
Figure above: Mean daily attack rate (total predation: continuous line, left Y axis) on dough (interrupted line, left Y axis) and clay (interrupted line, left Y axis) dummy caterpillars in Kibale National Park, Uganda. Attack rate is roughly congruent with mean daily rainfalls measured by a local data logger (bars, left Y axis), mean rainfall data collected during 70 years by a nearby meteorological station (bars, left Y axis) as well as inferred abundance of caterpillars (area with pattern, right Y axis). Statistical results of cross-correlation analyses are presented in Table 3. Data for whole year 2010 and beginning of year 2011 (behind interrupted vertical line) are shown.
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New lovely photos from research field trips 2015 are available here.
Congratulations to Lucia Chmurova!
Lucia finished her Master thesis in late August, and she waits for her evaluation now. We are also about to collect her last and problematic study site in late September, and get additional data ready for her publication.
We have been at ATBC conference in Honolulu in July 2015 - 20.7.2015
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We were excited to be able to attend ATBC conference again, this time in Honolulu in Hawaii. I managed to prepare two presentations - one talk about my new exclosure experiments, and a poster about my older work from elevational gradient. My husband was there presenting preliminary results form his PhD project about food-webs on ficus trees from Mt. Wilhelm gradient.
Here you can see some more photos from this lovely event - ALBUM Below, you can also download my talk and poster I presented there.
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New publication for second half of year 2014
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Ctvrtecka, R., Sam, K., Brus, E., Weiblen, G. D., & Novotny, V. (2014). Frugivorous weevils are too rare to cause Janzen–Connell effects in New Guinea lowland rain forest. Journal of Tropical Ecology, 30(06), 521-535. Pdf here.
A community of frugivorous weevils was studied by quantitative rearing of 57 weevil species represented by10485 individuals from 326 woody plant species in lowland rain forest in Papua New Guinea. Only fruits from 35% ofplant species were attacked by weevils. On average, weevils were reared from only 1 in 33 fruits and 1 kg of fruit wasattacked by 2.51 individuals. Weevil host specificity was relatively high: 42% of weevil species fed on a single plantgenus, 19% on a single plant family and only 16% were reared from more than one family. However, monophagousspecialists represented only 23% of all reared individuals. The average 1 kg of fruits was infested by 1.84 individualsof generalist weevils (feeding on allogeneric or allofamilial host species), 0.52 individual of specialists (feeding on asingle or several congeneric species), and 0.15 individual of unknown host specificity. Large-seeded fruits with thinmesocarp tended to host specialist species whereas those with thick, fleshy mesocarp were often infested with bothspecialists and generalists. Weevils tended to avoid small-seeded, fleshy fruits. The low incidence of seed damage (3%of seeds) suggests that weevils are unlikely to play a major role in regulating plant populations via density-dependentmortality processes outlined by the Janzen–Connell hypothesis. |
I have been at ATBC conference in Cairns - 26.7.2014
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Myself and my assistant Bonny Koane attended ATBC (Association for Tropical Biology Conservation) conference in Cairns, where we presented results of our two projects. I was talking about birds along elevational gradient, and Bonny was presenting results of our caterpillar-predation experiments along the elevational gradient (currently being published in Ecography - see below).
We had great time there, and I am proud of my son who was whole time on his best behavior. We have also taken this opportunity and worked with the ATBC Council on a resolution in support of postgraduate education, biological research funding and biodiversity conservation in PNG. The resolution was put together and approved by the conference. |
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I managed to publish few papers during last months - 20.7.2017
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Low, P. A., Sam, K., McArthur, C., Posa, M. R. C., Hochuli, D. F. 2014. Determining predator identity from attack marks left in model caterpillars: guidelines for best practice. Entomologia Experimentalis et Applicata. DOI: 10.1111/eea.12207
The use of model caterpillars to assess relative rates of predation has risen in popularity in recent years. However, there currently exists no detailed information on how to assign attack marks to particular predators. We aimed to address this gap by collating a comprehensive reference collection of the types of marks made by different predators to serve as a guide for researchers wanting to identify the predators responsible for attacks. To determine what level of resolution in identification may be considered reliable, we also tested the consistency of predator assignments made by different individuals. We found that predator identification at a coarse taxonomic level (i.e., bird, mammal, arthropod) was reasonably consistent. In contrast, when more fine-scale identification was attempted, the level of consistency and therefore also confidence in the accuracy of an identification was dramatically reduced, reflecting the difficulty of distinguishing between attacks made not only by different arthropod groups but also by differently sized birds and mammals. We recommend that identifications be made at a coarse taxonomic level and, where possible, by multiple researchers or team members. We also suggest that our collection of images of representative attack marks from each of the coarse predator categories, and descriptions of their defining characteristics, can serve as a guide to assist with identifications and this will be complemented by a good knowledge of the locally occurring and abundant predators. |
Example of bite marks: lizard Pseudothecadactylus lindneri (a-c); Northern giant cave gecko (d-f)
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Sam, K., Koane, B., Novotny, V. 2014. Herbivore damage increases avian and ant predation of caterpillars on trees along a complete elevational forest gradient in Papua New Guinea. Ecography. DOI: 10.1111/ecog.00979
Parasitic and predatory arthropods and insectivorous birds are among natural enemies of the herbivorous insect which can prevent plants from being severely damaged by herbivores. Recent studies show that plants suffering from an attack by herbivores can actively reduce the number of herbivorous insects by attracting predators; this phenomenon, known as ‘plants crying for help’, is due to a tritrophic interaction, in which the damaged plants are more attractive for natural enemies of herbivores. Signals given off by plants to alert predators to herbivore attack may provide exciting examples of coevolution among organisms from multiple trophic levels.
We examined whether signals from mechanically damaged trees (simulating damage by herbivores) attract predators of insects along a complete elevational rainforest gradient in tropical region, where various predators are expected to occur at particular elevational belts. We studied predation of artificial caterpillars on trees with and without ‘herbivorous’ damage; as well as diversity and abundances of potential predators at eight study sites along the elevational gradient (200–3700 m a.s.l.). We focused on attacks by ants and birds, as the main predators of herbivorous insect.
The predation rate decreased with elevation from 10% d-1 at 200 m a.s.l. to 1.8% d-1 at 3700 m a.s.l. Ants were relatively more important predators in the lowlands, while birds became dominant predators above 1700 m a.s.l. Caterpillars exposed on trees with herbivorous damage were attacked significantly more than caterpillars exposed on trees without damage. Results suggest that relative importance of predators varies along elevational gradient, and that observed predation rates correspond with abundances of predators. Results further show that herbivorous damage attracts both ants and birds, but its effect is stronger for ants.
Parasitic and predatory arthropods and insectivorous birds are among natural enemies of the herbivorous insect which can prevent plants from being severely damaged by herbivores. Recent studies show that plants suffering from an attack by herbivores can actively reduce the number of herbivorous insects by attracting predators; this phenomenon, known as ‘plants crying for help’, is due to a tritrophic interaction, in which the damaged plants are more attractive for natural enemies of herbivores. Signals given off by plants to alert predators to herbivore attack may provide exciting examples of coevolution among organisms from multiple trophic levels.
We examined whether signals from mechanically damaged trees (simulating damage by herbivores) attract predators of insects along a complete elevational rainforest gradient in tropical region, where various predators are expected to occur at particular elevational belts. We studied predation of artificial caterpillars on trees with and without ‘herbivorous’ damage; as well as diversity and abundances of potential predators at eight study sites along the elevational gradient (200–3700 m a.s.l.). We focused on attacks by ants and birds, as the main predators of herbivorous insect.
The predation rate decreased with elevation from 10% d-1 at 200 m a.s.l. to 1.8% d-1 at 3700 m a.s.l. Ants were relatively more important predators in the lowlands, while birds became dominant predators above 1700 m a.s.l. Caterpillars exposed on trees with herbivorous damage were attacked significantly more than caterpillars exposed on trees without damage. Results suggest that relative importance of predators varies along elevational gradient, and that observed predation rates correspond with abundances of predators. Results further show that herbivorous damage attracts both ants and birds, but its effect is stronger for ants.
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Sam, K., Koane, B. 2014. New avian records along the elevational gradient of Mt. Wilhelm, Papua New Guinea. Bulletin of the British Ornithologists’ Club 134(2): 116-133
In current paper, we describe avifauna of the mountain Mt. Wilhelm in Papua New Guinea. The north slopes of Mt. Wilhelm, the highest peak in Papua New Guinea, support a complete elevational gradient of relatively undisturbed rainforest, from 200 m to the tree line at 3,700 m. Based on field work in 2010 and 2012 over the Mt. Wilhelm elevational gradient, we report novel distribution data for 43 species, including geographic and elevational range extensions, demographic data, and new records of species poorly known in New Guinea. Our new data regarding avian distributions reveal that New Guinea continues to be an excellent theatre to study diversification, competition and community structure. We recorded many extensions to upper elevational ranges (7% of the total number of species), which is especially surprising considering the elevational distance of 500 m between sites, resulting in significant under-estimation of limits at in-between elevations, and that we did not consider potential extensions of < 100 m as significant. However, our main caveat is the absence of historical data for Mt. Wilhelm. Our new elevational records suggest that some species are expanding upslope in response to climate change. |
Melidectes princeps - 3700 m asl - Lake Aiunde camp
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Sam, K., Koane, B., Jeppy, S., & Novotny, V. 2014. Effect of forest fragmentation on bird species richness in Papua New Guinea. Journal of Field Ornithology 85(2): 152-167. DOI: 10.1111/jofo.12057
Tropical forests worldwide are being fragmented at a rapid rate, causing a tremendous loss of biodiversity. Determining the impacts of forest disturbance and fragmentation on tropical biotas is therefore a central goal of conservation biology. We focused on bird communities in the interior (>100 m from forest edge) of forest fragments (300, 600, and 1200 ha) in the lowlands of Papua New Guinea and compared them with those in continuous forest. We surveyed bird communities using point counts, mist-netting, and random walks, and measured habitat and microclimate characteristics at each site. We also surveyed leaf-dwelling arthropods, butterflies, and ants, and obtained diet samples from birds to examine food availability and food preferences. We recorded significantly fewer bird species per point in the 300-ha forest fragment than in other study sites. Overall, we recorded 80, 84, and 88 species, respectively, in forest fragments, and 102 in continuous forest. Frugivores (especially large frugivores) and insectivores had lower species richness in forest fragments than continuous forest. Our results did not support the food scarcity hypothesis, that is, the decline of insectivorous birds in forest fragments is caused by an impoverished invertebrate prey base. We also found no significant differences among forest fragments and continuous forest in microclimates of forest interiors. Rather, we found that microhabitats preferred by sensitive birds (i.e., 30% of species with the strongest preferences for continuous forest) were less common in forest fragments (19%–31% of points) than in continuous forest (86% of points). Our results suggest that changes in microhabitats may make forest fragments unsuitable for sensitive species. However, limited dispersal capabilities could also make some species of birds less likely to disperse and occupy fragments. In addition, impoverished food resources, size of the forest fragment, or hunting pressure could contribute to the absence of large frugivorous birds in forest fragments. The forest fragments in our study, preserved as village-based protected areas, were not large enough to sustain the bird communities found in continuous forest. However, because these fragments still contained numerous bird species, preservation of such areas can be an important component of management strategies to conserve rainforests and birds in Papua New Guinea. |
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