Observations on the intraspecific variation in tadpole morphology in natural ponds

Intraspecific morphological variation of anuran tadpoles occurs in response to several factors. Causes and consequences of this variation have been largely studied hitherto in controlled environments, but data from natural habitats is clearly less abundant. Here, we present a series of observations on the morphology – mainly tail depth – of three tadpole species from NE Iberian Peninsula across different pond typologies. According to experimental data on tadpole morphology and selective pressures along the pond permanency gradient, we should expect that tadpoles inhabiting ponds with a short hydroperiod – mainly facing desiccation risk – have shallower tail fins than tadpoles from ponds with longer hydroperiod – mainly facing predation risk. Thus, we expected that the link between these complementary selective pressures – predation risk, desiccation risk – and hydroperiod could make possible to detect intraspecific variation in tadpole morphology among different typologies of natural ponds. Morphological differences were found in all studied species, and variation, when present, agreed with theory: tadpoles had deeper fin tails as they were collected in ponds with a longer hydroperiod. Interestingly, in most cases these morphological differences were more marked as tadpoles were larger in size. Although distances among the studied ponds were generally short – posing phenotypic plasticity as the most plausible proximate mechanism – specifically designed studies would be needed to disentangle the relative role of other processes like local adaptation

Observations on the intraspecific variation in tadpole morphology in natural ponds

Intraspecific morphological variation of anuran tadpoles occurs in response to several factors. Causes and consequences of this variation have been largely studied hitherto in controlled environments, but data from natural habitats is clearly less abundant. Here, we present a series of observations on the morphology – mainly tail depth – of three tadpole species from NE Iberian Peninsula across different pond typologies. According to experimental data on tadpole morphology and selective pressures along the pond permanency gradient, we should expect that tadpoles inhabiting ponds with a short hydroperiod – mainly facing desiccation risk – have shallower tail fins than tadpoles from ponds with longer hydroperiod – mainly facing predation risk. Thus, we expected that the link between these complementary selective pressures – predation risk, desiccation risk – and hydroperiod could make possible to detect intraspecific variation in tadpole morphology among different typologies of natural ponds. Morphological differences were found in all studied species, and variation, when present, agreed with theory: tadpoles had deeper fin tails as they were collected in ponds with a longer hydroperiod. Interestingly, in most cases these morphological differences were more marked as tadpoles were larger in size. Although distances among the studied ponds were generally short – posing phenotypic plasticity as the most plausible proximate mechanism – specifically designed studies would be needed to disentangle the relative role of other processes like local adaptation

Micro-hotspots for conservation: an umbrella tree species for the unique Socotran reptile fauna

Umbrella species are defined as species that can be rare and sensitive to human disturbance, whose protection may confer the protection of other co-occurring species. The dragon's blood tree Dracaena cinnabari Balf.f. was already considered an umbrella species on Socotra Island (Indic Ocean, Yemen) due to its ecological importance for some native biota. We studied the reptile community living on D. cinnabari from Socotra Island. We sampled reptiles on trees across most D. cinnabari populations and applied co-occurrence and network partition analyses to check if the presence of reptiles on D. cinnabari populations was random or structured. Regardless of its patched and scarce actual distribution, we report the use of this tree as a habitat by more than half of the reptile community (12 endemic reptiles). Co-occurrence and network partition analyses demonstrate that this community is structured across the distribution of dragon's blood trees, reflecting complex allopatric, vicariant, and biotic interaction processes. Hence, these trees act as micro-hotspots for reptiles, that is, as areas where endemic and rare species that are under threat at the landscape scale co-occur. This Socotra endemic tree is currently threatened by overgrazing, overmaturity, and climate change. Its protection and declaration as an umbrella species are expected to benefit the reptile community and to protect evolutionary processes that are partially driven by the ecological links between reptiles and this tree. To our knowledge, no tree species has been proposed as an umbrella species for island vertebrate endemics so far, highlighting the ecological uniqueness of Socotra Island

Differential trophic traits between invasive and native anuran tadpoles

How trophic resources are managed is a key factor in our understanding of the success of invasive species. In amphibians that usually occupy ephemeral ponds, the capacity to acquire resources and food selection are especially important because as a pond dries, the larval density increases and food resources are limited. Abundant and high-quality food can increase the final size and reduce the duration of development of amphibians. The aim of this work was to assess the trophic traits of tadpoles of the invasive (originally North African) anuran Discoglossus pictus compared to those of native European Epidalea calamita tadpoles under laboratory conditions. Food of two different levels of quality was supplied, and the feeding activity and food preference of the two species were analysed alone and in co-occurrence. D. pictus was capable of modifying its behaviour and food preferences; while E. calamita displayed much milder differences between treatments. Both alone and in co-occurrence with the native species, the invasive tadpoles obtained higher feeding activity values and showed a stronger preference for high-quality food. Additionally, when high densities of the two species shared food resources, the feeding activity results indicated potential displacement of the native tadpoles to lowquality resources. D. pictus thus presents trophic traits that are favourable for invasion and could limit the fitness of E. calamita when resources are limited or there is a risk of pond desiccation

Stable isotopes and diet uncover trophic-niche divergence and ecological diversification processes of endemic reptiles on Socotra Island

Ecological diversification on islands typically results in divergence of ecological niches. As diet is a majorcomponent of species niches, we hypothesize that sister species within island monophyletic groupsdiversify in their dietary preferences. We have examined this hypothesis in two Haemodracon and fourHemidactylus species endemic reptiles of from Socotra Island (Yemen), corresponding to two indepen-dent colonization events. Convergence i.e., similar dietary patterns of phylogenetically unrelated species,was also examined. Trophic niches were studied by the analysis of carbon and nitrogen stable isotopescombined with faecal samples. We collected tail tips (for isotopes) and faecal pellets during two visitsin 2013 and 2014 to Socotra. Specific trophic niche widths inferred from stable isotopes were estimatedfrom ellipse-based metrics, whereas interspecific differences were compared by linear mixed models andexamined in a phylogenetic framework. From faecal samples, diet variation among species was quanti-fied by the Bray-Curtis index. Isotope and dietary interspecific divergence was compared with Manteltests. For both isotopes, models detected interspecific differences between sister species i.e., trophic nichedivergence and also interspecific similarities of distant lineages that use similar microhabitats i.e., ecolog-ical convergence. We did not find any phylogenetic signal neither in the interspecific differences in 13Cnor in 15N isotopic values; thus species phylogenetically more closely related did not have more similarisotopic niches. The Mantel test demonstrated similar interspecific divergence using isotopes and faecalsamples. In a phylogenetic context, trophic-niche interspecific comparisons highlight some mechanismsthat are driving ecological diversification and speciation of Socotra Island

Impacts of use and abuse of nature in Catalona with proposal for sustainable management

This paper provides an overview of the last 40 years of use, and in many cases abuse, of the natural resources in Catalonia, a country that is representative of European countries in general, and especially those in the Mediterranean region. It analyses the use of natural resources made by mining, agriculture, livestock, logging, fishing, nature tourism, and energy production and consumption. This use results in an ecological footprint, i.e., the productive land and sea surface required to generate the consumed resources and absorb the resulting waste, which is about seven times the amount available, a very high number but very similar to other European countries. This overexploitation of natural resources has a huge impact on land and its different forms of cover, air, and water. For the last 25 years, forests and urban areas have each gained almost 3% more of the territory at the expense of agricultural land; those municipalities bordering the sea have increased their number of inhabitants and activity, and although they only occupy 6.7% of the total surface area, they account for 43.3% of the population; air quality has stabilized since the turn of the century, and there has been some improvement in the state of aquatic ecosystems, but still only 36% are in good condition, while the remainder have suffered morphological changes and different forms of nonpoint source pollution; meanwhile the biodiversity of flora and fauna remains still under threat. Environmental policies do not go far enough so there is a need for revision of the legislation related to environmental impact and the protection of natural areas, flora, and fauna. The promotion of environmental research must be accompanied by environmental education to foster a society which is more knowledgeable, has more control and influence over the decisions that deeply affect it. Indeed, nature conservation goes hand in hand with other social and economic challenges that require a more sustainable vision. Today's problems with nature derive from the current economic model, which is environmentally unsustainable in that it does not take into account environmental impacts. Lastly, we propose a series of reasonable and feasible priority measures and actions related to each use made of the country's natural resources, to the impacts they have had, and to their management, in the hope that these can contribute to improving the conservation and management of the environment and biodiversity and move towards sustainability

Impacts of Use and Abuse of Nature in Catalonia with Proposals for Sustainable Management

This paper provides an overview of the last 40 years of use, and in many cases abuse, of the natural resources in Catalonia, a country that is representative of European countries in general, and especially those in the Mediterranean region. It analyses the use of natural resources made by mining, agriculture, livestock, logging, fishing, nature tourism, and energy production and consumption. This use results in an ecological footprint, i.e., the productive land and sea surface required to generate the consumed resources and absorb the resulting waste, which is about seven times the amount available, a very high number but very similar to other European countries. This overexploitation of natural resources has a huge impact on land and its different forms of cover, air, and water. For the last 25 years, forests and urban areas have each gained almost 3% more of the territory at the expense of agricultural land; those municipalities bordering the sea have increased their number of inhabitants and activity, and although they only occupy 6.7% of the total surface area, they account for 43.3% of the population; air quality has stabilized since the turn of the century, and there has been some improvement in the state of aquatic ecosystems, but still only 36% are in good condition, while the remainder have suffered morphological changes and different forms of nonpoint source pollution; meanwhile the biodiversity of flora and fauna remains still under threat. Environmental policies do not go far enough so there is a need for revision of the legislation related to environmental impact and the protection of natural areas, flora, and fauna. The promotion of environmental research must be accompanied by environmental education to foster a society which is Land 2021, 10, 144 3 of 53 more knowledgeable, has more control and influence over the decisions that deeply affect it. Indeed, nature conservation goes hand in hand with other social and economic challenges that require a more sustainable vision. Today’s problems with nature derive from the current economic model, which is environmentally unsustainable in that it does not take into account environmental impacts. Lastly, we propose a series of reasonable and feasible priority measures and actions related to each use made of the country’s natural resources, to the impacts they have had, and to their management, in the hope that these can contribute to improving the conservation and management of the environment and biodiversity and move towards sustainability.info:eu-repo/semantics/publishedVersio

Biological invasions: a temporal, spatial and plastic point of view: the case of Discoglossus pictus in Europe = Invasions biològiques: un punt de vista temporal, espaial i plàstic: el cas de Discoglossus pictus a Europa

[eng] The rates at which allochthonous species are introduced and become invasive worldwide are unprecedented and accordingly, the number of studies on invasion biology have increased during the past years. However, biological invasions are still seemingly underused as natural laboratories to test essential biological theory. In this sense, the nine studies – ordered in three parts, which function as thematic blocks – presented in this thesis try to globally give an evolutionary – apart from ecologic – point of view on the ongoing invasion of the Mediterranean Painted Frog (Discoglossus pictus) in Europe. This frog is native to Northern Africa and was introduced from Algeria in Southern France approximately a century ago, being nowadays present on a wide coastal strip of approximately 250km in SE France and NE Spain, constantly colonizing new areas. The aim of “PART A: Intraspecific variation along the invasive range of Discoglossus pictus” is the examination at a phenotypic and genomic level of possible differences across populations within the invasive range of the species. We observe that the Mediterranean Painted Frog is not a uniform unit in its invasive range in Europe: mean size of adults and life-history traits related to mean annual precipitation, while substantial genetic differences among populations are most probably created by the expansion history itself. The aim of “PART B: Intraguild competition in tadpoles of Discoglossus pictus” is to study and discuss the role of Discoglossus pictus tadpoles as potential competitors for the larvae of native anurans. We here see that the Mediterranean Painted Frog represents, physiologically, a unique addition to the local tadpole guild, characterized by a very rapid and consumption-oriented growth, and that these tadpoles are able to increase the quality and quantity of its food intake when these possibilities are provided. This poses these tadpoles as potentially very disruptive of the natural dynamics of native anurans. Concerning the competitive relationship between the Natterjack Toad (Epidalea calamita) and the Mediterranean Painted Frog, we can observe that it changes according to previous evolutionary history of populations. In this sense, populations of the native toad that have had a greater number of generations of contact with the invasive frog are able to inflict a greater competitive distress on the invasive tadpoles. Both competitors also differ mildly in their breeding preferences, but nevertheless, both species seem forced to end up competing very often at a pond level. Within ponds, the trophic position of both species can respond either to evolutionary or to ecological patterns with the data gathered hitherto. Finally, in “PART C: Tadpoles of Discoglossus pictus as prey for aquatic native predators”, two studies examine if invasive tadpoles modify its phenotypes in front of an array of – native and invasive – predators, testing also the effectiveness of the possible changes. Interestingly, the invasive frog presents a pattern of inducible defences which would be expected for a native anuran, responding to all native predators effectively, while lacking responses in front of introduced or invasive predators. Globally, the complex evolutionary history of the local anuran assemblages poses the Mediterranean Painted Frog as a good model for ecological and evolutionary studies reaching beyond invasion biology, as it is very particular case of invasive species, in which effects of previous recurrent shared evolutionary history with similar competitor / predator species are probably present.[cat] Les invasions biològiques estan essent aparentment infrautilitzades com a laboratoris naturals per investigar certs aspectes teòrics fonamentals de la biologia. En aquest sentit, els nou estudis presentats en aquesta tesi – ordenats en tres blocs temàtics – intenten donar un punt de vista evolutiu – a part d'ecològic – sobre la invasió de la granota pintada (Discoglossus pictus) a Europa. Aquesta granota es va introduir des d'Algèria a Banyuls de la Marenda (Catalunya Nord) fa aproximadament un segle, arribant ara des de Montpeller fins a Sant Celoni, colonitzant contínuament noves àrees. A la "PART A: variabilitat intraespecífica al llarg de la distribució invasora de Discoglossus pictus" observem que la granota pintada no forma un conjunt uniforme de poblacions en la seva distribució invasora europea, ni fenotípica ni genòmicament: la mida i els trets de la història vital dels adults es relacionen amb la precipitació mitjana de cada zona, mentre que la diferenciació genètica entre poblacions ha estat molt probablement creada pel procés d'expansió en sí. A la "PART B: Competència intra-gremi en capgrossos de Discoglossus pictus" veiem que la granota pintada representa, fisiològicament, una addició única al gremi local de capgrossos, caracteritzada per un creixement molt ràpid i orientat al consum, amb bones capacitats d'augmentar la qualitat i quantitat de la ingesta d'aliments quan n'hi ha possibilitats. Pel que fa a la freqüent relació de competència entre Epidalea calamita i Discoglossus pictus, podem observar que els capgrossos autòctons que han tingut un major nombre de generacions de contacte amb els invasors són capaços d'infligir un major estrès competitiu en aquests. Els dos competidors també difereixen lleugerament en les seves preferències de cria, però semblen estar obligats a acabar competint molt sovint a nivell de bassa. Dins d'aquestes, la posició tròfica d'ambdues espècies pot respondre tant a patrons evolutius com a patrons ecològics amb les dades recollides fins ara. Finalment, a la "Part C: Capgrossos de Discoglossus pictus com a presa per depredadors aquàtics autòctons" veiem que la granota invasora presenta un patró de defenses induïbles que s'emmotlla al que s'esperaria per a un anur autòcton, responent a tots els depredadors nadius eficaçment, mancant respostes davant de depredadors introduïts. La complexa història evolutiva dels conjunts d'anurs del mediterrani occidental posa la granota pintada com un cas molt particular d'espècie invasora, on no ses poden descartar els efectes d'una història co-evolutiva prèvia entre espècies similars

Predation on Trachylepis socotrana by Lanius meridionalis

El alcaudón sureño (Lanius meridionalis) es un depredador común de reptiles, conocido por empalar sus capturas en arbustos espinosos como reserva. El 3 de Marzo de 2014, después de detectar un ejemplar de L. meridionalis alrededor de nuestro campamento en la reserva forestal de Firmhin (Socotra), encontramos unos restos de Trachylepis socotrana empalados en una rama seca. Durante los diversos muestreos que tuvieron lugar ese año en Firmhin, ese escincido no se detectó, lo que indica la posible importancia del examen de este tipo de restos para detectar poblaciones de reptiles con poca densidad en ambientes insulares.This work was undertaken with the support of The Mohamed bin Zayed Species Conservation Fund, project nº 13055714, and grant CGL2012-36970 from the Ministerio de Economía y Competitividad, Spain (co-funded by FEDER). R. Vasconcelos and X. Santos are supported by Postdoctoral grants from the Fundação para a Ciência e Tecnologia (FCT) (SFRH/BPD/79913/2011 and SFRH/BPD/73176/2010). The Environmental Protection Agency (EPA) aided and permitted the field work in Socotra.Peer reviewe