Life histories, ecological tolerance limits, and the evolution of geographic range size in Eucalyptus (Myrtaceae)

2005 ◽  
Vol 53 (6) ◽  
pp. 501 ◽  
Author(s):  
Sally Mathews ◽  
Stephen P. Bonser
Keyword(s):  
Life History ◽  
Drought Tolerance ◽  
Life Histories ◽  
Spatial Scales ◽  
Geographic Range ◽  
Range Size ◽  
Tolerance Limits ◽  
Physiological Tolerance ◽  
Australian Continent ◽  
The Impact

Current theories explaining variability in species geographic range sizes in plants tend to focus on how traits associated with either physiological tolerance limits or life histories are related to range size. In trees, aspects of both physiological tolerance (e.g. drought tolerance) and life history (e.g. life span and growth rate) are related to stem traits such as wood density and height relative to diameter. We examined how the evolution of stem traits is related to geographic range sizes in Eucalyptus at two spatial scales: across the Australian continent and within the wet forests near the east coast of Australia. Geographic range sizes were estimated from herbarium records. Stem trait data were collected from both natural populations and published sources. We used phylogenetically independent contrasts to test for evolutionary associations between stem traits and geographic range sizes. Across Australia, the evolution of stem traits conferring drought tolerance were not consistently associated greater range sizes. This was surprising since arid and semi-arid environments are geographically expansive. Within the eastern forests, the evolution of stem traits defining slow growing, competitively dominant life histories were associated with greater range sizes. These stem traits should confer both a capacity to disperse into previously unoccupied habitats and the ability to persist in habitats already occupied. Traits associated with physiological tolerance and life history had significant effects on the evolution of range sizes in Eucalyptus. However, we demonstrate that the impact of these traits on range size evolution depends on both environmental conditions and the scale at which these traits are examined.

scholarly journals Slow Life History Leaves Endangered Snake Vulnerable to Illegal Poaching

2020 ◽  
Author(s):  
Chris Jolly ◽  
Brenton von Takach ◽  
Jonathan Webb
Keyword(s):  
Life History ◽  
Population Growth ◽  
Life Histories ◽  
Extinction Risk ◽  
Adult Mortality ◽  
Sensitivity Analyses ◽  
Wildlife Trade ◽  
Pet Trade ◽  
The Impact ◽  
Negative Population

Abstract Global wildlife trade is a multibillion-dollar industry and a significant driver of vertebrate extinction risk. Yet, few studies have quantified the impact of wild harvesting for the illicit pet trade on populations. Long-lived species, by virtue of their slow life history characteristics, may be unable to sustain even low levels of harvesting. Here, we assessed the impact of illegal poaching on a metapopulation of endangered broad-headed snakes (Hoplocephalus bungaroides) at gated (protected) and ungated (unprotected) populations. Because broad-headed snakes are long-lived, grow slowly and reproduce infrequently, populations are likely vulnerable to increases in adult mortality. Long-term data revealed that annual survival rates of snakes were significantly lower in the ungated population than the gated population, consistent with the hypothesis of human removal of snakes for the pet trade. Population viability analysis showed that the ungated population has a strongly negative population growth rate and is only prevented from ultimate extinction by dispersal of small numbers of individuals from the gated population. Sensitivity analyses showed that the removal of a small number of adult females was sufficient to impose negative population growth and suggests that threatened species with slow life histories are likely to be especially vulnerable to illegal poaching.

Issues Based on Species Life History and Behavior

2021 ◽  
pp. 89-94
Author(s):  
Joseph A. Veech
Keyword(s):  
Life History ◽  
Habitat Use ◽  
Life Histories ◽  
Radio Telemetry ◽  
Spatial Scales ◽  
Habitat Associations ◽  
Habitat Characteristics ◽  
Habitat Analysis ◽  
The Individual ◽  
And Behavior

Species vary tremendously in their life histories and behavior. The particular life history traits and behavior of the focal species must be considered when designing a study to examine habitat associations. For some species, individuals use different areas (of the landscape or territory) for breeding and foraging. As such, the important characteristics for the foraging and breeding habitats may be different. The dramatically different life stages of some organisms (e.g., amphibians and some insects) often correspond to equally dramatic differences in habitat use between juveniles and adults. For some species, habitat use differs among seasons. Species that are highly mobile and have individuals that move around substantially on a daily or weekly basis are particularly challenging for a habitat analysis. For these species, the most efficient and appropriate study design may be one that tracks individuals (through radio-telemetry or GPS) and analyzes the environmental or habitat characteristics at locations where the individual has stopped, rather than trying to survey for the species in pre-established and insufficiently small survey plots. In addition, individual movement and the issues mentioned above may necessitate that environmental variables are measured and analyzed at multiple spatial scales.

Large-scale variation in life history traits of the widespread diadromous fish, Galaxias maculatus, reflects geographic differences in local environmental conditions

2011 ◽  
Vol 62 (7) ◽  
pp. 790 ◽  
Author(s):  
Nicole C. Barbee ◽  
Robin Hale ◽  
John Morrongiello ◽  
Andy Hicks ◽  
David Semmens ◽  
...  
Keyword(s):  
Life History ◽  
South America ◽  
Environmental Conditions ◽  
Life Histories ◽  
Large Scale ◽  
Life History Traits ◽  
Spatial Scales ◽  
Local Conditions ◽  
Widespread Species ◽  
Galaxias Maculatus

Applying uniform population models and management strategies to widespread species can be ineffective if populations exhibit variable life histories in response to local conditions. Galaxias maculatus, one of the world’s most widely distributed fish species, occurs in a broad range of habitats and is highly adaptable, making it an ideal species for examining variation in life history traits across large geographic scales. Here, we examine the spawning biology and early life history of diadromous G. maculatus in coastal rivers in Victoria, Australia, and compare them to other populations throughout its range. We predicted that traits associated with these critical life stages, especially those that respond to environmental conditions that vary geographically, such as seasonal cues and temperature, are likely to vary across large spatial scales. We found that spawning occurs later in Victoria than in New Zealand (NZ) and South America, but migration back to rivers occurs at the same time in Victoria and NZ, but not South America. G. maculatus returning to rivers are also smaller and younger in Victoria than those in NZ. Other traits, like some attributes of spawning schools and spawning habitats, did not vary across large scales. Researchers and managers should be cautious when making broad assumptions about the biology of widely distributed species.

scholarly journals Simulating the effects of local adaptation and life history on the ability of plants to track climate shifts

AoB Plants ◽  
2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Emily V Moran
Keyword(s):  
Climate Change ◽  
Local Adaptation ◽  
Life Histories ◽  
Range Size ◽  
Range Shift ◽  
Range Shifts ◽  
Climate Shift ◽  
Management Actions ◽  
Climate Shifts ◽  
The Impact

Abstract Many studies have examined the impact of dispersal on local adaptation, but much less attention has been paid to how local adaptation influences range shifts. The aim of this study was to test how local adaptation might affect climate-driven range shifts in plants, and if this might differ between plants with different life histories. Simulated range shift dynamics were compared for hypothetical annual, perennial and tree species, each comprised of either one plastic genotype or six locally adapted genotypes. The landscape consists of shifting climate bands made up of 20 × 20 m patches containing multiple individuals. Effects of seed dispersal, breadth of the plastic species’ tolerance, steepness of the climate gradient and rate of the climate shift are also examined. Local adaptation increased the equilibrium range size and aided range shifts by boosting fitness near range edges. However, when the rate of climate change was doubled on a steep gradient, locally adapted trees exhibited a higher percent loss of range during the climate shift. The plastic annual species with short dispersal was unable to recover its range size even after the climate stabilized, while the locally adapted annuals tracked climate change well. The results suggest that in most situations local adaptation and longer dispersal distances will be advantageous, though not necessarily sufficient, for tracking suitable climates. However, local adaptation might put species with long generation times at greater risk when climate shifts are very rapid. If confirmed by empirical tests, these results suggest that identifying variation between species in how fitness varies along climate gradients and in these key demographic rates might aid in prioritizing management actions.

The impact of geographic range, sampling, ecology, and time on extinction risk in the volatile clade Graptoloida

Paleobiology ◽  
2016 ◽  
Vol 43 (1) ◽  
pp. 85-113 ◽  
Author(s):  
James Boyle ◽  
H. David Sheets ◽  
Shuang-Ye Wu ◽  
Daniel Goldman ◽  
Michael J. Melchin ◽  
...  
Keyword(s):  
Ecological Niche ◽  
Extinction Risk ◽  
Biological Effects ◽  
Abiotic Factors ◽  
Explanatory Power ◽  
Negative Relationship ◽  
Geographic Range ◽  
Range Size ◽  
Age Cohorts ◽  
The Impact

AbstractAlthough extinction risk has been found to have a consistent negative relationship with geographic range across wide temporal and taxonomic scales, the effect has been difficult to disentangle from factors such as sampling, ecological niche, or clade. In addition, studies of extinction risk have focused on benthic invertebrates with less work on planktic taxa. We employed a global set of 1114 planktic graptolite species from the Ordovician to lower Devonian to analyze the predictive power of species’ traits and abiotic factors on extinction risk, combining general linear models (GLMs), partial least-squares regression (PLSR), and permutation tests. Factors included measures of geographic range, sampling, and graptolite-specific factors such as clade, biofacies affiliation, shallow water tolerance, and age cohorts split at the base of the Katian and Rhuddanian stages.The percent variance in durations explained varied substantially between taxon subsets from 12% to 45%. Overall commonness, the correlated effects of geographic range and sampling, was the strongest, most consistent factor (12–30% variance explained), with clade and age cohort adding up to 18% and other factors <10%. Surprisingly, geographic range alone contributed little explanatory power (<5%). It is likely that this is a consequence of a nonlinear relationship between geographic range and extinction risk, wherein the largest reductions in extinction risk are gained from moderate expansion of small geographic ranges. Thus, even large differences in range size between graptolite species did not lead to a proportionate difference in extinction risk because of the large average ranges of these species. Finally, we emphasize that the common practice of determining the geographic range of taxa from the union of all occurrences over their duration poses a substantial risk of overestimating the geographic scope of the realized ecological niche and, thus, of further conflating sampling effects on observed duration with the biological effects of range size on extinction risk.

scholarly journals Ecology of New Zealand Deep-sea Chondrichthyans

2021 ◽  
Author(s):  
◽  
Brit Finucci
Keyword(s):  
Life History ◽  
New Zealand ◽  
Deep Sea ◽  
Life Histories ◽  
Biological Data ◽  
Trawl Survey ◽  
Depth Range ◽  
Ontogenetic Changes ◽  
Adult Females ◽  
The Impact

<p>Deep-sea chondrichthyans represent nearly half of the known species of sharks, rays, and chimaeras. Most are poorly known, largely due to their historically low economic value, and thus, low prioritization for research efforts and targeted sampling. Globally, many deep-sea fisheries have proven to be unsustainable, as deep-sea species are generally characterised with life history traits, resulting in low biological productivity. Although generally not targeted, there is a lack of data on New Zealand deep-sea chondrichthyans, despite regularly occurring as bycatch, with no mitigation in place to limit catches.   This thesis described aspects of life histories for data deficient deep-sea chondrichthyans caught as bycatch in New Zealand deep-sea fisheries. In Chapter II, research trawl survey data were used to describe and evaluate length-weight relationships, which were found to greatly differ from parameters reported by FishBase. This was followed by the application of a set of models to detect changes in weight at length relationships, and assess if these changes correspond to biological or ecological events, such as length-at-maturity or ontogenetic changes in diet.   Chapter III evaluates deep-sea chondrichthyan aggregations and social associations. Not all species were found to engage in aggregative behaviour, but those that did suggested patterns of sex- and size-specific associations which varied with catch density. Adult females were caught most frequently in low densities and were highly associated with other adult females, adult males consistently highly associated with each other, and the highest density catches were dominated by juvenile individuals. These trends may be driven by factors such as foraging, predator avoidance or sexual conflict avoidance.   Chapters IV, V, and VI examine, respectively, details of the reproduction, life history, and diet of prickly dogfish (Oxynotus bruniensis), longnose spookfish (Harriotta raleighana) and Pacific spookfish (Rhinochimaera pacifica), and brown chimaera (Chimaera carophila) and black ghost shark (Hydrolagus homonycteris). All species were found to have life histories characteristic of low productivity, including reaching maturation at a large proportion of their maximum length, and having low fecundity. Additional novel biological results included: DNA identification of prey revealed that O. bruniensis preyed exclusively on the egg capsules of holocephalans, potentially making it the only known elasmobranch with a diet reliant solely upon other chondrichthyans; sperm storage was confirmed in female H. raleighana, R. pacifica, and C. carophila; and sexual dimorphism in snout length was found in H. raleighana, where male relative snout size increased at sexual maturity, suggesting that the snout is a secondary sexual characteristic.   The depth range of most New Zealand deep-sea chondrichthyans may provide some refuge from current fishing activity. However, results from this thesis have suggested that the species examined here have life histories characteristic of low productivity, and engage in behaviours that will have implications for selective mortality by spatially or temporally stratified fishing. Oxynotus bruniensis, in particular, is likely at higher risk from the impact of fishing than currently estimated, given its reproductive characteristics, highly specialised diet, and distribution overlap with deep-sea fisheries. Continued monitoring and a greater collection of biological data from additional and alternative sources (e.g. fisheries observer program, local fishers, underwater vehicles and video) is recommended to fully understand and negate mortality from human activities.</p>

scholarly journals Slow life history leaves endangered snake vulnerable to illegal collecting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chris J. Jolly ◽  
Brenton Von Takach ◽  
Jonathan K. Webb
Keyword(s):  
Life History ◽  
Population Growth ◽  
Life Histories ◽  
Extinction Risk ◽  
Adult Mortality ◽  
Sensitivity Analyses ◽  
Wildlife Trade ◽  
Pet Trade ◽  
The Impact ◽  
Negative Population

AbstractGlobal wildlife trade is a multibillion-dollar industry and a significant driver of vertebrate extinction risk. Yet, few studies have quantified the impact of wild harvesting for the illicit pet trade on populations. Long-lived species, by virtue of their slow life history characteristics, may be unable to sustain even low levels of collecting. Here, we assessed the impact of illegal collecting on populations of endangered broad-headed snakes (Hoplocephalus bungaroides) at gated (protected) and ungated (unprotected) sites. Because broad-headed snakes are long-lived, grow slowly and reproduce infrequently, populations are likely vulnerable to increases in adult mortality. Long-term data revealed that annual survival rates of snakes were significantly lower in the ungated population than the gated population, consistent with the hypothesis of human removal of snakes for the pet trade. Population viability analysis showed that the ungated population has a strongly negative population growth rate and is only prevented from ultimate extinction by dispersal of small numbers of individuals from the gated population. Sensitivity analyses showed that the removal of a small number of adult females was sufficient to impose negative population growth and suggests that threatened species with slow life histories are likely to be especially vulnerable to illegal collecting.

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