staff

Claudio Quilodrán

External collaborator in Anthropology & Evolutionary Simulations

  • T: +41 22 379 69 61
  • office 4-421 (Sciences II)

External collaborator in Vertebrate evolution

  • T: +41 22 379 30 67
  • office 4081B (Sciences III)
  • Modelling interspecific hybridization with genome exclusion to identify conservation actions: the case of native and invasive Pelophylax waterfrogs. Evol Appl 2015 Feb;8(2):199-210. 10.1111/eva.12245. PMC4319866.

    abstract

    Interspecific hybridization occurs in nature but can also be caused by human actions. It often leads to infertile or fertile hybrids that exclude one parental genome during gametogenesis, escaping genetic recombination and introgression. The threat that genome-exclusion hybridization might represent on parental species is poorly understood, especially when invasive species are involved. Here, we show how to assess the effects of genome-exclusion hybridization and how to elaborate conservation actions by simulating scenarios using a model of nonintrogressive hybridization. We examine the case of the frog Pelophylax ridibundus, introduced in Western Europe, which can hybridize with the native Pelophylax lessonae and the pre-existing hybrid Pelophylax esculentus, maintained by hybridogenesis. If translocated from Southern Europe, P. ridibundus produces new sterile hybrids and we show that it mainly threatens P. esculentus. Translocation from Central Europe leads to new fertile hybrids, threatening all native waterfrogs. Local extinction is demographically mediated via wasted reproductive potential or via demographic flow through generations towards P. ridibundus. We reveal that enlarging the habitat size of the native P. lessonae relative to that of the invader is a promising conservation strategy, avoiding the difficulties of fighting the invader. We finally stress that nonintrogressive hybridization is to be considered in conservation programmes.

    view more details on Pubmed

  • Models of hybridization during range expansions and their application to recent human evolution In book: Cultural Developments in the Eurasian Paleolithic and the Origin of Anatomically Modern Humans, Publisher: Derevianko, AP; Shunkov, M, pp.122-137

    abstract

    see on external website

  • Conspecific effect on habitat selection of a territorial cavity-nesting bird The Wilson Journal of Ornithology 09/2014; 126:534-543. DOI: 10.1676/13-108.1

    abstract

    The simulated presence of conspecifics has been proposed to attract territorial songbirds to protect nesting areas when the habitat is being disturbed by human activities. We studied the effects of conspecifics on the nest-site selection of the Thorn-tailed Rayadito (Aphrastura spinicauda; Furnariidae), a forest songbird that depends on cavities for nesting.Plantations represent usable habitat for foraging, but the scarcity of cavities restricts their use during the breeding period. The use of nest boxes is a documented measure to mitigate the negative effect of plantations on cavity users. We installed nest boxes in a plantation ofPinus radiata in south-central Chile, using the simulated presence of conspecifics as a potential tool to attract rayaditos to new available sites to nest. We simulated the presence of conspecifics through playback during 45 days prior nest building. Our results showed two contrasting outcomes. Firstly, conspecific simulation attracts rayaditos, by increasing their density before playback experiments by 75%. Secondly, rayaditos tended to avoid playback treatment sites as nesting started. The establishment of nests occurred 71%of the time and started 20 days earlier in control sites compared to playback treatment. Other secondary cavity-nesting birds, such as the House Wren (Troglodytes aedon;Troglodytidae) andWhite-throated Tree runner (Pygarrhichas albogularis; Furnariidae), also avoided playback plots as nesting sites. The scarcity of cavities in pine plantations may increase the aggressive defense of breeding territories, making cavity-nesting birds move to other previously known vacant sites to nest when they listen other birds in the nesting site. It is highly recommended to assess the behavioral response to conspecific and heterospecific birds before the establishment of a management measure aiming to attract or discourage the presence of a target species.

    see on external website

  • A general model of distant hybridization reveals the conditions for extinction in Atlantic salmon and brown trout. PLoS ONE 2014 ;9(7):e101736. 10.1371/journal.pone.0101736. PONE-D-14-07667. PMC4086968.

    abstract

    Interspecific hybridization is common in nature but can be increased in frequency or even originated by human actions, such as species introduction or habitat modification, which may threaten species persistence. When hybridization occurs between distantly related species, referred to as "distant hybridization," the resulting hybrids are generally infertile or fertile but do not undergo chromosomal recombination during gametogenesis. Here, we present a model describing this frequent but poorly studied interspecific hybridization to assess its consequences on parental species and to anticipate the conditions under which they can reach extinction. Our general model fully incorporates three important processes: density-dependent competition, dominance/recessivity inheritance of traits and assortative mating. We demonstrate its use and flexibility by assessing population extinction risk between Atlantic salmon and brown trout in Norway, whose interbreeding has recently increased due to farmed fish releases into the wild. We identified the set of conditions under which hybridization may threaten salmonid species. Thanks to the flexibility of our model, we evaluated the effect of an additional risk factor, a parasitic disease, and showed that the cumulative effects dramatically increase the extinction risk. The consequences of distant hybridization are not genetically, but demographically mediated. Our general model is useful to better comprehend the evolution of such hybrid systems and we demonstrated its importance in the field of conservation biology to set up management recommendations when this increasingly frequent type of hybridization is in action.

    view more details on Pubmed

  • Nest-Site Selection and Success of Red Shoveler (Anas platalea) in a Wetland of Central Chile Waterbirds 36(1):102-107. 2013

    abstract

    Understanding the factors that determine waterfowl nesting site selection is an essential tool for wetland management, but, unfortunately, this information is lacking for most species in the Southern Hemisphere. During the 2007 breeding season, reproductive biology and nesting habitat selection of the Red Shoveler (Anas platalea) were investigated in a wetland of Central Chile. Red Shoveler nests were clumped, primarily in scrubby meadows, containing an average of 8.56 ± 1 eggs (n = 2 3). Nesting microhabitat was characterized by well-covered ground and an intermediate height of the rich herbaceous layer close to the water. Hatching success was 80 ± 20% and was negatively associated with the number of cattle dung piles and the proportion of dry vegetation, but positively explained by herbaceous height and the distance to watercourse. Results suggest that the risk of predation, the access to food, and cattle disturbance would affect the selection of breeding sites and nest success of Red Shoveler. Management should focus on increasing diversity the herbaceous layer, ensuring easy access to water sources, and decreasing livestock pressure during the nesting period.

    see on external website

  • Nesting of the Thorn-Tailed Rayadito (Aphrastura spinicauda) in a Pine Plantation in Southcentral Chile The Wilson Journal of Ornithology. 12/2012; 124(4):737-742. DOI: 10.2307/23324523

    abstract

    We installed nest boxes for Thorn-tailed Rayaditos (Aphrastrura spinicauda) and monitored their use in a Monterrey pine (Pinus radiata) plantation in the Maule Region, south central Chile. Thirty-four breeding pairs built nests in boxes, of which 75% began laying eggs. Nest establishment began in early September and construction lasted 12.8 ± 4.9 days (n = 23). Rayaditos used mainly pine needles, together with mosses, epiphytes, herbs, and animal hair in their nests. Clutch size ranged from two to four eggs (mode = 3) that were incubated for 15.8 ± 1.2 days. Brood size negatively affected mass of nestlings, but was positively related to mass of the parents. Adults had higher body mass and built larger nests than those reported previously for the species on Chiloé Island, where broods are larger and the incubation period is shorter. The provision of artificial cavities allowed Thorn-tailed Rayaditos to nest in the pine plantation. Nest boxes combined with other management tools, such as maintaining snags and understory enhancement, may be important factors in mitigation of negative effects of pine plantations on secondary cavity-nesting birds.

    see on external website

Biodiversity loss by interspecific hybridization

Natural hybridization has played an important role in the evolution of many plant and animal taxa. However, when hybridization is caused by anthropogenic factors, it may lead to serious consequences for biological conservation. This is particularly true in native rare or threatened species, because if the population size is too small we expect a gradual replacement of their genotype by hybrids.

This research project aims to model the impact of anthropogenic changes on the genetic integrity of organisms due to interspecific hybridization. We will highlight the potential effects of exotic invasive species and habitat modifications, due in particular to global climate change. Global warming will impact rainfall regimes and result in a reduction of river flow, especially in small tributaries and headwaters. As a consequence, freshwater organisms will be forced to respond with downstream population displacements, leading to new interactions among populations and species. The fish of the family Cyprinidae are used as model organisms as they represent most of the fish biodiversity in European continental waters and because they are particularly subject to interspecific hybridization.

In the first part of this project we will develop a simple model based on two well-studied species inhabiting the Rhône basin that display natural and viable hybrids: Rutilus rutilus x Abramis brama. In the second part, the influence of non-native invasive species that can hybridize with local species will be added to the model.

The final goal of this project is to estimate under which conditions the increasing rate of hybridization can affect the extinction risk of freshwater organisms and to provide guidance concerning the kind of data required to propose potential conservation strategies.