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1.
Environ Manage ; 72(3): 519-528, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-36781454

RESUMEN

Global-scale ecological changes and intensifying habitat destruction and have caused alarming declines in wildlife populations, resulting in a great need for concerted efforts towards their conservation. Despite this, animals are frequently overlooked in restoration and management initiatives and therefore populations often do not reassemble following disturbance without re-establishing habitat that meets their abiotic and biotic requirements. However, restoration ecologists broadly lack insight into the physiological mechanisms that can govern the responses of fauna to environmental change and management. Therefore, we conducted a literature search for studies reporting a mechanistic understanding of faunal habitat suitability and selection in restored landscapes to deliver an updated perspective on the integration of animal ecophysiology and restoration ecology. Of the 75,442 studies that we identified discussing ecological restoration in the last 50 years, only 8,627 (11.4%) did so in the context of fauna from which 912 studies (1.2%) examined habitat selection, 35 studies (0.05%) integrated physiology and only 15 studies (0.02%) explored thermal biology, despite temperature being one of the most pervasive drivers of physiological functioning. To combat this, we developed a conceptual framework that can guide restoration ecophysiology and promote innovative, multidisciplinary research through an established adaptive management structure. While physiological tools and approaches are currently underutilised in restoration practice, integrating them into ecological restoration, and environmental management more broadly, will offer exciting new opportunities to describe, explain and predict the responses of fauna to environmental change occurring, and that yet to come.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Animales , Conservación de los Recursos Naturales/métodos , Animales Salvajes
2.
Mol Ecol ; 31(16): 4307-4318, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35775282

RESUMEN

Studies of insecticide resistance provide insights into the capacity of populations to show rapid evolutionary responses to contemporary selection. Malaria control remains heavily dependent on pyrethroid insecticides, primarily in long lasting insecticidal nets (LLINs). Resistance in the major malaria vectors has increased in concert with the expansion of LLIN distributions. Identifying genetic mechanisms underlying high-level resistance is crucial for the development and deployment of resistance-breaking tools. Using the Anopheles gambiae 1000 genomes (Ag1000g) data we identified a very recent selective sweep in mosquitoes from Uganda which localized to a cluster of cytochrome P450 genes. Further interrogation revealed a haplotype involving a trio of mutations, a nonsynonymous point mutation in Cyp6p4 (I236M), an upstream insertion of a partial Zanzibar-like transposable element (TE) and a duplication of the Cyp6aa1 gene. The mutations appear to have originated recently in An. gambiae from the Kenya-Uganda border, with stepwise replacement of the double-mutant (Zanzibar-like TE and Cyp6p4-236 M) with the triple-mutant haplotype (including Cyp6aa1 duplication), which has spread into the Democratic Republic of Congo and Tanzania. The triple-mutant haplotype is strongly associated with increased expression of genes able to metabolize pyrethroids and is strongly predictive of resistance to pyrethroids most notably deltamethrin. Importantly, there was increased mortality in mosquitoes carrying the triple-mutation when exposed to nets cotreated with the synergist piperonyl butoxide (PBO). Frequencies of the triple-mutant haplotype remain spatially variable within countries, suggesting an effective marker system to guide deployment decisions for limited supplies of PBO-pyrethroid cotreated LLINs across African countries.


Asunto(s)
Anopheles , Antimaláricos , Mosquiteros Tratados con Insecticida , Insecticidas , Malaria , Piretrinas , Animales , Anopheles/genética , Antimaláricos/farmacología , Resistencia a los Insecticidas/genética , Insecticidas/farmacología , Kenia , Malaria/prevención & control , Mosquitos Vectores/genética , Patología Molecular , Piretrinas/farmacología
3.
Conserv Biol ; 36(1): e13667, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-33210780

RESUMEN

Mitigation translocation is a subgroup of conservation translocation, categorized by a crisis-responsive time frame and the immediate goal of relocating individuals threatened with death. However, the relative successes of conservation translocations with longer time frames and broader metapopulation- and ecosystem-level considerations have been used to justify the continued implementation of mitigation translocations without adequate post hoc monitoring to confirm their effectiveness as a conservation tool. Mitigation translocations now outnumber other conservation translocations, and understanding the effectiveness of mitigation translocations is critical given limited global conservation funding especially if the mitigation translocations undermine biodiversity conservation by failing to save individuals. We assessed the effectiveness of mitigation translocations by conducting a quantitative review of the global literature. A total of 59 mitigation translocations were reviewed for their adherence to the adaptive scientific approach expected of other conservation translocations and for the testing of management options to continue improving techniques for the future. We found that mitigation translocations have not achieved their potential as an effective applied science. Most translocations focused predominantly on population establishment- and persistence-level questions, as is often seen in translocations more broadly, and less on metapopulation and ecosystem outcomes. Questions regarding the long-term impacts to the recipient ecosystem (12% of articles) and the carrying capacity of translocation sites (24% of articles) were addressed least often, despite these factors being more likely to influence ultimate success. Less than half (47%) of studies included comparison of different management techniques to facilitate practitioners selecting the most effective management actions for the future. To align mitigation translocations with the relative success of other conservation translocations, it is critical that future mitigation translocations conform to an established experimental approach to improve their effectiveness. Effective mitigation translocations will require significantly greater investment of time, expertise, and resources in the future.


La Translocación para Mitigación como una Herramienta de Gestión Resumen La translocación para mitigación es un subgrupo de la translocación para la conservación, caracterizada por un marco de tiempo que responda a la crisis y la meta inmediata de reubicar a individuos amenazados de muerte. Sin embargo, el éxito relativo de las traslocaciones para conservación con marcos de tiempo mayores y consideraciones a nivel metapoblación y ecosistema más amplias han sido utilizadas para justificar la implementación de translocaciones para mitigación sin monitoreo post hoc adecuado para confirmar su efectividad como herramienta de conservación. Las translocaciones para mitigación ahora son más numerosas que otras translocaciones, por lo que es fundamental entender la efectividad de las translocaciones para mitigación debido a las limitaciones en el financiamiento para la conservación global - especialmente si las translocaciones para mitigación socavan la conservación de la biodiversidad al fallar en salvar individuos. Evaluamos la efectividad de translocaciones para mitigación mediante una revisión cuantitativa de la literatura global. Revisamos un total de 59 translocaciones para mitigación para analizar su adhesión al método científico adaptativo esperado de otras translocaciones de conservación y para probar las opciones de gestión para mejorar las técnicas en el futuro. Encontramos que las mitigaciones para translocación no han alcanzado su potencial como una ciencia aplicada efectiva. La mayoría de las translocaciones se centraron predominantemente en preguntas relacionadas con el establecimiento y nivel de persistencia de la población, como se observa en translocaciones más generales, y menos en resultados a nivel metapoblación y ecosistema. Aspectos relacionados con los impactos a largo plazo sobre el ecosistema recipiente (12% de los artículos) y la capacidad de carga de los sitios de translocación (24% de los artículos) fueron poco abordados, no obstante que es más probable que estos factores influyan en el éxito final. Menos de la mitad (47%) de los estudios incluyó la comparación de métodos de gestión diferentes para facilitar que los practicantes selecciones las acciones de gestión más efectivas para el futuro. Para alinear las translocaciones para mitigación con el éxito relativo de otras translocaciones para conservación, es crítico que las futuras translocaciones para mitigación se apeguen a un método experimental establecido para incrementar su efectividad. Para ser efectivas, las translocaciones para mitigación requerirán una inversión de tiempo, conocimientos técnicos y recursos significativamente mayores.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Biodiversidad , Conservación de los Recursos Naturales/métodos , Humanos , Motivación
4.
Mol Biol Evol ; 37(10): 2900-2917, 2020 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-32449755

RESUMEN

The evolution of insecticide resistance mechanisms in natural populations of Anopheles malaria vectors is a major public health concern across Africa. Using genome sequence data, we study the evolution of resistance mutations in the resistance to dieldrin locus (Rdl), a GABA receptor targeted by several insecticides, but most notably by the long-discontinued cyclodiene, dieldrin. The two Rdl resistance mutations (296G and 296S) spread across West and Central African Anopheles via two independent hard selective sweeps that included likely compensatory nearby mutations, and were followed by a rare combination of introgression across species (from A. gambiae and A. arabiensis to A. coluzzii) and across nonconcordant karyotypes of the 2La chromosomal inversion. Rdl resistance evolved in the 1950s as the first known adaptation to a large-scale insecticide-based intervention, but the evolutionary lessons from this system highlight contemporary and future dangers for management strategies designed to combat development of resistance in malaria vectors.


Asunto(s)
Anopheles/genética , Dieldrín , Evolución Molecular , Introgresión Genética , Animales , Inversión Cromosómica , Proteínas de Drosophila , Haplotipos , Resistencia a los Insecticidas/genética , Mutación , Receptores de GABA-A , Selección Genética
5.
Ann Bot ; 128(3): 329-343, 2021 08 26.
Artículo en Inglés | MEDLINE | ID: mdl-34077492

RESUMEN

BACKGROUND AND AIMS: Mycorrhizal fungi are a critical component of the ecological niche of most plants and can potentially constrain their geographical range. Unlike other types of mycorrhizal fungi, the distributions of orchid mycorrhizal fungi (OMF) at large spatial scales are not well understood. Here, we investigate the distribution and diversity of Ceratobasidium OMF in orchids and soils across the Australian continent. METHODS: We sampled 217 Ceratobasidium isolates from 111 orchid species across southern Australia and combined these with 311 Ceratobasidium sequences from GenBank. To estimate the taxonomic diversity of Ceratobasidium associating with orchids, phylogenetic analysis of the ITS sequence locus was undertaken. Sequence data from the continent-wide Australian Microbiome Initiative were used to determine the geographical range of operational taxonomic units (OTUs) detected in orchids, with the distribution and climatic correlates of the two most frequently detected OTUs modelled using MaxEnt. KEY RESULTS: We identified 23 Ceratobasidium OTUs associating with Australian orchids, primarily from the orchid genera Pterostylis, Prasophyllum, Rhizanthella and Sarcochilus. OTUs isolated from orchids were closely related to, but distinct from, known pathogenic fungi. Data from soils and orchids revealed that ten of these OTUs occur on both east and west sides of the continent, while 13 OTUs were recorded at three locations or fewer. MaxEnt models suggested that the distributions of two widespread OTUs are correlated with temperature and soil moisture of the wettest quarter and far exceeded the distributions of their host orchid species. CONCLUSIONS: Ceratobasidium OMF with cross-continental distributions are common in Australian soils and frequently have geographical ranges that exceed that of their host orchid species, suggesting these fungi are not limiting the distributions of their host orchids at large spatial scales. Most OTUs were distributed within southern Australia, although several OTUs had distributions extending into central and northern parts of the continent, illustrating their tolerance of an extraordinarily wide range of environmental conditions.


Asunto(s)
Basidiomycota , Micorrizas , Australia , Basidiomycota/genética , Micorrizas/genética , Filogenia , Simbiosis
6.
New Phytol ; 221(4): 1764-1775, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30269352

RESUMEN

Trait-based approaches have improved our understanding of plant evolution, community assembly and ecosystem functioning. A major challenge for the upcoming decades is to understand the functions and evolution of early life-history traits, across levels of organization and ecological strategies. Although a variety of seed traits are critical for dispersal, persistence, germination timing and seedling establishment, only seed mass has been considered systematically. Here we suggest broadening the range of morphological, physiological and biochemical seed traits to add new understanding on plant niches, population dynamics and community assembly. The diversity of seed traits and functions provides an important challenge that will require international collaboration in three areas of research. First, we present a conceptual framework for a seed ecological spectrum that builds upon current understanding of plant niches. We then lay the foundation for a seed-trait functional network, the establishment of which will underpin and facilitate trait-based inferences. Finally, we anticipate novel insights and challenges associated with incorporating diverse seed traits into predictive evolutionary ecology, community ecology and applied ecology. If the community invests in standardized seed-trait collection and the implementation of rigorous databases, major strides can be made at this exciting frontier of functional ecology.


Asunto(s)
Germinación/fisiología , Dispersión de Semillas/fisiología , Semillas/fisiología , Biodiversidad , Conservación de los Recursos Naturales , Bases de Datos Factuales , Ecosistema , Plantones/fisiología
7.
J Therm Biol ; 81: 49-58, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30975423

RESUMEN

Although several approaches have been suggested, there is no broadly accepted single approach for quantitative characterization of thermal performance in ectotherms. I sought to identify the most appropriate non-linear function with which to represent thermal performance of ectothermic metabolic rate, and to interrogate the biological relevance of the thermal parameters of this function. I used published data for exercise-induced metabolic rates of eight species of reptile from a broad phylogenetic base and global distribution. Using an Akaike Information Criterion, I compared 12 different models proposed to characterize thermal performance adapted from a broad range of disciplines, finding that a beta-distribution model described the reptile metabolic rate data most parsimoniously. Using the beta-distribution model, unique functions were parameterized for each species. Four parameters were extracted from each species-specific fit: the temperature coincident with the peak of the thermal performance curve, Topt; the point at which the function intersected the x-axis, CTmax; and two points indicative of thermal breadth, Td(lower) and Td(upper). There was a positive relationship between the species' preferred body temperatures (Tpref) reported in the scientific literature and both Topt and Td(lower) extracted from the species-specific beta functions. While Td(lower) estimates were not different to published Tpref values, Topt estimates were statistically higher than Tpref. This is consistent with previous observations that the point of peak performance does not match Tpref. The predicted CTmax also correlated well with published values. The model in its current form was not able to estimate CTmin, and this parameter was not explored here, but should be in future research. By providing a quantitative description of the thermal performance, the beta-distribution function offers a new theoretical basis for thermal optimality. I contend that Tpref aligns with the mathematical threshold Td(lower), where metabolic rate is at its maximum prior to thermal inhibition.


Asunto(s)
Regulación de la Temperatura Corporal , Lagartos/metabolismo , Termotolerancia , Animales , Modelos Biológicos , Modelos Teóricos , Dinámicas no Lineales , Análisis de Regresión , Especificidad de la Especie , Temperatura
8.
BMC Genomics ; 19(1): 225, 2018 03 27.
Artículo en Inglés | MEDLINE | ID: mdl-29587635

RESUMEN

BACKGROUND: To combat malaria transmission, the Ugandan government has embarked upon an ambitious programme of indoor residual spraying (IRS) with a carbamate class insecticide, bendiocarb. In preparation for this campaign, we characterized bendiocarb resistance and associated transcriptional variation among Anopheles gambiae s.s. mosquitoes from two sites in Uganda. RESULTS: Gene expression in two mosquito populations displaying some resistance to bendiocarb (95% and 79% An. gambiae s.l. WHO tube bioassay mortality in Nagongera and Kihihi, respectively) was investigated using whole-genome microarrays. Significant overexpression of several genes encoding salivary gland proteins, including D7r2 and D7r4, was detected in mosquitoes from Nagongera. In Kihihi, D7r4, two detoxification-associated genes (Cyp6m2 and Gstd3) and an epithelial serine protease were among the genes most highly overexpressed in resistant mosquitoes. Following the first round of IRS in Nagongera, bendiocarb-resistant mosquitoes were collected, and real-time quantitative PCR analyses detected significant overexpression of D7r2 and D7r4 in resistant mosquitoes. A single nucleotide polymorphism located in a non-coding transcript downstream of the D7 genes was found at a significantly higher frequency in resistant individuals. In silico modelling of the interaction between D7r4 and bendiocarb demonstrated similarity between the insecticide and serotonin, a known ligand of D7 proteins. A meta-analysis of published microarray studies revealed a recurring association between D7 expression and insecticide resistance across Anopheles species and locations. CONCLUSIONS: A whole-genome microarray approach identified an association between novel insecticide resistance candidates and bendiocarb resistance in Uganda. In addition, a single nucleotide polymorphism associated with this resistance mechanism was discovered. The use of such impartial screening methods allows for discovery of resistance candidates that have no previously-ascribed function in insecticide binding or detoxification. Characterizing these novel candidates will broaden our understanding of resistance mechanisms and yield new strategies for combatting widespread insecticide resistance among malaria vectors.


Asunto(s)
Anopheles/genética , Proteínas de Insectos/genética , Resistencia a los Insecticidas , Insecticidas/farmacología , Polimorfismo de Nucleótido Simple , Glándulas Salivales/metabolismo , Animales , Anopheles/clasificación , Anopheles/efectos de los fármacos , Genoma de los Insectos , Glándulas Salivales/efectos de los fármacos , Glándulas Salivales/parasitología
9.
J Exp Biol ; 221(Pt 7)2018 04 06.
Artículo en Inglés | MEDLINE | ID: mdl-29444841

RESUMEN

We explore a recent, innovative variation of closed-system respirometry for terrestrial organisms, whereby oxygen partial pressure (PO2 ) is repeatedly measured fluorometrically in a constant-volume chamber over multiple time points. We outline a protocol that aligns this technology with the broader literature on aerial respirometry, including the calculations required to accurately convert O2 depletion to metabolic rate (MR). We identify a series of assumptions, and sources of error associated with this technique, including thresholds where O2 depletion becomes limiting, that impart errors to the calculation and interpretation of MR. Using these adjusted calculations, we found that the resting MR of five species of angiosperm seeds ranged from 0.011 to 0.640 ml g-1 h-1, consistent with published seed MR values. This innovative methodology greatly expands the lower size limit of terrestrial organisms that can be measured, and offers the potential for measuring MR changes over time as a result of physiological processes of the organism.


Asunto(s)
Metabolismo Basal , Semillas/metabolismo , Espirometría/métodos , Acacia/metabolismo , Australia , Fluorescencia , Senna/metabolismo
10.
Proc Biol Sci ; 284(1848)2017 02 08.
Artículo en Inglés | MEDLINE | ID: mdl-28179522

RESUMEN

Field metabolic rate (FMR) links the energy budget of an animal with the constraints of its ecosystem, but is particularly difficult to measure for small organisms. Landscape degradation exacerbates environmental adversity and reduces resource availability, imposing higher costs of living for many organisms. Here, we report a significant effect of landscape degradation on the FMR of free-flying Apis mellifera, estimated using 86Rb radio-isotopic turnover. We validated the relationship between 86Rb kb and metabolic rate for worker bees in the laboratory using flow-through respirometry. We then released radioisotopically enriched individuals into a natural woodland and a heavily degraded and deforested plantation. FMRs of worker bees in natural woodland vegetation were significantly higher than in a deforested landscape. Nectar consumption, estimated using 22Na radio-isotopic turnover, also differed significantly between natural and degraded landscapes. In the deforested landscape, we infer that the costs of foraging exceeded energetic availability, and honeybees instead foraged less and depended more on stored resources in the hive. If this is generally the case with increasing landscape degradation, this will have important implications for the provision of pollination services and the effectiveness and resilience of ecological restoration practice.


Asunto(s)
Abejas/metabolismo , Ecosistema , Néctar de las Plantas , Animales
11.
J Exp Biol ; 219(Pt 10): 1552-62, 2016 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-26994173

RESUMEN

Seasonal acclimatisation of thermal tolerance, evaporative water loss and metabolic rate, along with regulation of the hive environment, are key ways whereby hive-based social insects mediate climatic challenges throughout the year, but the relative importance of these traits remains poorly understood. Here, we examined seasonal variation in metabolic rate and evaporative water loss of worker bees, and seasonal variation of hive temperature and relative humidity (RH), for the stingless bee Austroplebeia essingtoni (Apidae: Meliponini) in arid tropical Australia. Both water loss and metabolic rate were lower in the cooler, dry winter than in the hot, wet summer at most ambient temperatures between 20°C and 45°C. Contrary to expectation, thermal tolerance thresholds were higher in the winter than in the summer. Hives were cooler in the cooler, dry winter than in the hot, wet summer, linked to an apparent lack of hive thermoregulation. The RH of hives was regulated at approximately 65% in both seasons, which is higher than unoccupied control hives in the dry season, but less than unoccupied control hives in the wet season. Although adaptations to promote water balance appear more important for survival of A. essingtoni than traits related to temperature regulation, their capacity for water conservation is coincident with increased thermal tolerance. For these small, eusocial stingless bees in the arid tropics, where air temperatures are relatively high and stable compared with temperate areas, regulation of hive humidity appears to be of more importance than temperature for maintaining hive health.


Asunto(s)
Abejas/fisiología , Humedad , Comportamiento de Nidificación/fisiología , Temperatura , Animales , Metabolismo Basal/fisiología , Peso Corporal/fisiología , Clima , Modelos Biológicos , Estaciones del Año , Pérdida Insensible de Agua
12.
J Therm Biol ; 57: 54-65, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27033039

RESUMEN

The calculation and comparison of physiological characteristics of thermoregulation has provided insight into patterns of ecology and evolution for over half a century. Thermoregulation has typically been explored using linear techniques; I explore the application of non-linear scaling to more accurately calculate and compare characteristics and thresholds of thermoregulation, including the basal metabolic rate (BMR), peak metabolic rate (PMR) and the lower (Tlc) and upper (Tuc) critical limits to the thermo-neutral zone (TNZ) for Australian rodents. An exponentially-modified logistic function accurately characterised the response of metabolic rate to ambient temperature, while evaporative water loss was accurately characterised by a Michaelis-Menten function. When these functions were used to resolve unique parameters for the nine species studied here, the estimates of BMR and TNZ were consistent with the previously published estimates. The approach resolved differences in rates of metabolism and water loss between subfamilies of Australian rodents that haven't been quantified before. I suggest that non-linear scaling is not only more effective than the established segmented linear techniques, but also is more objective. This approach may allow broader and more flexible comparison of characteristics of thermoregulation, but it needs testing with a broader array of taxa than those used here.


Asunto(s)
Algoritmos , Metabolismo Basal , Regulación de la Temperatura Corporal , Especies Introducidas , Roedores/fisiología , Pérdida Insensible de Agua , Animales , Australia , Especificidad de la Especie , Termometría/métodos
13.
Artículo en Inglés | MEDLINE | ID: mdl-26384457

RESUMEN

A typical explanation for ecologically stable strategies that apply to only a proportion of a population, is bet hedging, where increased reproductive success offsets reduced reproductive rate. One such is partial migration, where only a proportion of a population moves seasonally to avoid inclement climatic conditions. Bet hedging may overlook unseen costs to maintain broad physiological resilience, implied by encountering a breadth of environmental conditions. We investigated the physiological correlates of partial migration by measuring standard metabolic rates, and rates of evaporative water loss, and then estimating upper and lower thermal tolerance in males and females of two hoverfly species, Episyrphus balteatus and Eristalis tenax. In central Europe, females of these species may either migrate or overwinter, whereas males may migrate south to the Mediterranean, but have not been found overwintering. Both species were sexually dimorphic; female Ep. balteatus were lighter than males, but female Er. tenax were heavier than males. While allometrically- corrected metabolic rate in both species increased with temperature, the most parsimonious models included no sex-specific differences in metabolic rate for either species. Evaporative water loss of both species also increased with temperature, but was higher for females of both species than males. Assuming that resting metabolism is congruent with the activity requirements of migration, highly consistent thermal tolerance and metabolic rate suggests that any given fly could migrate, although water loss patterns suggest that females may be less well-adapted to Mediterranean climates. We infer that partial migration probably results from the imperatives of their reproductive strategies.


Asunto(s)
Migración Animal , Metabolismo Basal , Agua Corporal/metabolismo , Dípteros/fisiología , Metabolismo Energético , Modelos Biológicos , Adaptación Fisiológica , Animales , Agua Corporal/química , Peso Corporal , Dióxido de Carbono/metabolismo , Frío/efectos adversos , Femenino , Masculino , Región Mediterránea , Actividad Motora , Estaciones del Año , Caracteres Sexuales , Especificidad de la Especie , Suiza , Volatilización
14.
J Exp Biol ; 217(Pt 7): 1040-5, 2014 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-24363421

RESUMEN

The measurement of (86)Rb turnover recently has been suggested as a useful method for measuring field metabolic rate in small animals. We investigated a proposed mechanism of (86)Rb turnover, its analogy to K(+), by comparing the turnover of (86)Rb in a model insect, the rhinoceros beetle Xylotrupes gideon, fed a diet of plum jam or plum jam enriched with K(+) or Rb(+). The turnover of (86)Rb in the beetles on the K(+) and the Rb(+) diets was higher than that for beetles on the jam diet (F2,311=32.4; P=1.58×10(-13)). We also exposed the beetles to different ambient temperatures to induce differences in metabolic rate ( ) while feeding them the jam and K(+) diets. was higher at higher ambient temperature (Ta) for both jam (F1,11=14.56; P=0.003) and K(+) (F1,8=15.39; P=0.004) dietary groups, and the turnover of (86)Rb was higher at higher Ta for both jam (F1,11=10.80; P=0.007) and K(+) (F1,8=12.34; P=0.008) dietary groups. There was a significant relationship between (86)Rb turnover and for both the jam (F1,11=35.00; P=1.0×10(-3)) and the K(+) (F1,8=64.33; P=4.3×10(-5)) diets, but the relationship differed between the diets (F1,19=14.07; P=0.001), with a higher (86)Rb turnover in beetles on the K(+)-enriched than on the jam diet at all Ta. We conclude that (86)Rb turnover is related to K(+) metabolism, and that this is the mechanism of the relationship between (86)Rb turnover and . Studies relating (86)Rb turnover to should maintain dietary [K] as close as possible to that of natural diets for the most accurate calibrations for free-ranging animals.


Asunto(s)
Escarabajos/metabolismo , Metabolismo Energético , Potasio/metabolismo , Radioisótopos de Rubidio/metabolismo , Animales , Femenino , Masculino , Potasio en la Dieta/metabolismo , Rubidio/metabolismo , Temperatura
15.
Ann Bot ; 113(1): 55-67, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24284819

RESUMEN

BACKGROUND AND AIMS: Few phylogeographic studies have been undertaken of species confined to narrow, linear coastal systems where past sea level and geomorphological changes may have had a profound effect on species population sizes and distributions. In this study, a phylogeographic analysis was conducted of Eucalyptus gomphocephala (tuart), a tree species restricted to a 400 × 10 km band of coastal sand-plain in south west Australia. Here, there is little known about the response of coastal vegetation to glacial/interglacial climate change, and a test was made as to whether this species was likely to have persisted widely through the Last Glacial Maximum (LGM), or conforms to a post-LGM dispersal model of recovery from few refugia. METHODS: The genetic structure over the entire range of tuart was assessed using seven nuclear (21 populations; n = 595) and four chloroplast (24 populations; n = 238) microsatellite markers designed for eucalypt species. Correlative palaeodistribution modelling was also conducted based on five climatic variables, within two LGM models. KEY RESULTS: The chloroplast markers generated six haplotypes, which were strongly geographically structured (GST = 0·86 and RST = 0·75). Nuclear microsatellite diversity was high (overall mean HE 0·75) and uniformly distributed (FST = 0·05), with a strong pattern of isolation by distance (r(2) = 0·362, P = 0·001). Distribution models of E. gomphocephala during the LGM showed a wide distribution that extended at least 30 km westward from the current distribution to the palaeo-coastline. CONCLUSIONS: The chloroplast and nuclear data suggest wide persistence of E. gomphocephala during the LGM. Palaeodistribution modelling supports the conclusions drawn from genetic data and indicates a widespread westward shift of E. gomphocephala onto the exposed continental shelf during the LGM. This study highlights the importance of the inclusion of complementary, non-genetic data (information on geomorphology and palaeoclimate) to interpret phylogeographic patterns.


Asunto(s)
Eucalyptus/genética , Genética de Población , Repeticiones de Microsatélite , Núcleo Celular/genética , Cloroplastos/genética , Cambio Climático , Variación Genética , Haplotipos/genética , Cubierta de Hielo , Paleontología , Filogeografía , Australia del Sur
16.
Conserv Physiol ; 12(1): coae030, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38798718

RESUMEN

Defining plant ecophysiological responses across natural distributions enables a greater understanding of the niche that plants occupy. Much of the foundational knowledge of species' ecology and responses to environmental change across their distribution is often lacking, particularly for rare and threatened species, exacerbating management and conservation challenges. Combining high-resolution species distribution models (SDMs) with ecophysiological monitoring characterized the spatiotemporal variation in both plant traits and their interactions with their surrounding environment for the range-restricted Aluta quadrata Rye & Trudgen, and a common, co-occurring generalist, Eremophila latrobei subsp. glabra (L.S.Sm.) Chinnock., from the semi-arid Pilbara and Gascoyne region in northwest Western Australia. The plants reflected differences in gas exchange, plant health and plant water relations at sites with contrasting suitability from the SDM, with higher performance measured in the SDM-predicted high-suitability site. Seasonal differences demonstrated the highest variation across ecophysiological traits in both species, with higher performance in the austral wet season across all levels of habitat suitability. The results of this study allow us to effectively describe how plant performance in A. quadrata is distributed across the landscape in contrast to a common, widespread co-occurring species and demonstrate a level of confidence in the habitat suitability modelling derived from the SDM in predicting plant function determined through intensive ecophysiology monitoring programmes. In addition, the findings also provide a baseline approach for future conservation actions, as well as to explore the mechanisms underpinning the short-range endemism arid zone systems.

17.
Conserv Physiol ; 12(1): coae009, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38487732

RESUMEN

Seed germination responses for most narrow-range endemic species are poorly understood, imperilling their conservation management in the face of warming and drying terrestrial ecosystems. We quantified the realized microclimatic niches and the hydrothermal germination thresholds in four threatened taxa (Tetratheca erubescens, Tetratheca harperi, Tetratheca paynterae subsp. paynterae and Tetratheca aphylla subsp. aphylla) that are restricted to individual Banded Ironstone Formations in Western Australia. While T. aphylla subsp. aphylla largely failed to germinate in our trials, all other species demonstrated extended hydrothermal time accumulation (186-500°C MPa days), cool minimum temperatures (7.8-8.5°C), but broad base water potential thresholds (-2.46 to -5.41 MPa) under which germination occurred. These slow germination dynamics are suggestive of cool and wet winter months, where soil moisture is retained to a greater capacity in local microsites where these species occur, rather than the warmer and drier conditions in the surrounding arid environment. Hydrothermal time-to-event modelling showed that each species occupied unique hydrothermal germination niches, which correspond with the microclimatic differences the species are exposed to. Our results provide a baseline understanding for environmental and germination thresholds that govern the recruitment, and ultimately the population structure and persistence, of these short-range endemic plants. In addition, our results can aid future conservation, as well as restoration actions such as translocation to bolster population numbers and to mitigate against losses due to anthropogenic disturbance and global environmental change.

18.
Sci Rep ; 14(1): 5261, 2024 03 04.
Artículo en Inglés | MEDLINE | ID: mdl-38438419

RESUMEN

Drivers and dynamics of initial human migrations across individual islands and archipelagos are poorly understood, hampering assessments of subsequent modification of island biodiversity. We developed and tested a new statistical-simulation approach for reconstructing the pattern and pace of human migration across islands at high spatiotemporal resolutions. Using Polynesian colonisation of New Zealand as an example, we show that process-explicit models, informed by archaeological records and spatiotemporal reconstructions of past climates and environments, can provide new and important insights into the patterns and mechanisms of arrival and establishment of people on islands. We find that colonisation of New Zealand required there to have been a single founding population of approximately 500 people, arriving between 1233 and 1257 AD, settling multiple areas, and expanding rapidly over both North and South Islands. These verified spatiotemporal reconstructions of colonisation dynamics provide new opportunities to explore more extensively the potential ecological impacts of human colonisation on New Zealand's native biota and ecosystems.


Asunto(s)
Biodiversidad , Ecosistema , Humanos , Biota , Arqueología , Actividades Humanas
19.
Conserv Physiol ; 11(1): coad038, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37287992

RESUMEN

Global warming is now predicted to exceed 1.5°C by 2033 and 2°C by the end of the 21st century. This level of warming and the associated environmental variability are already increasing pressure on natural and human systems. Here we emphasize the role of physiology in the light of the latest assessment of climate warming by the Intergovernmental Panel on Climate Change. We describe how physiology can contribute to contemporary conservation programmes. We focus on thermal responses of animals, but we acknowledge that the impacts of climate change are much broader phylogenetically and environmentally. A physiological contribution would encompass environmental monitoring, coupled with measuring individual sensitivities to temperature change and upscaling these to ecosystem level. The latest version of the widely accepted Conservation Standards designed by the Conservation Measures Partnership includes several explicit climate change considerations. We argue that physiology has a unique role to play in addressing these considerations. Moreover, physiology can be incorporated by institutions and organizations that range from international bodies to national governments and to local communities, and in doing so, it brings a mechanistic approach to conservation and the management of biological resources.

20.
Animals (Basel) ; 13(16)2023 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-37627385

RESUMEN

Translocation science has made considerable progress over the last two decades; however, reptile translocations still frequently fail around the world. Major knowledge gaps surround the basic ecology of reptile species, including basic factors such as habitat preference, which have a critical influence on translocation success. The western spiny-tailed skink (Egernia stokesii badia) is used here as a case study to exemplify how empirical research can directly inform on-ground management and future translocation planning. A combination of studies, including LiDAR scanning of microhabitat structures, camera trapping, plasticine replica model experiments and unbounded point count surveys to assess predation risk, and visual and DNA analysis of dietary requirements, were all used to better understand the ecological requirements of E. s. badia. We found that the skinks have specific log pile requirements, both native and non-native predator management requirements, and a largely herbivorous, broad diet, which all influence translocation site selection and management planning. The use of E. s. badia as an Australian case study provides a clear strategic framework for the targeted research of meaningful ecological factors that influence translocation decision-making. Similar approaches applied to other reptile species are likely to fundamentally increase the capacity for effective management, and the likelihood of future successful translocations.

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