Dormancy and flowering in two mariposa lilies (Calochortus) with contrasting distribution patterns

2004 ◽  
Vol 82 (12) ◽  
pp. 1790-1799 ◽  
Author(s):  
Michael T Miller ◽  
Geraldine A Allen ◽  
Joseph A Antos
Keyword(s):  
Fruit Set ◽  
External Factor ◽  
Distribution Patterns ◽  
Range Limits ◽  
Perennial Species ◽  
Range Limit ◽  
Deer Herbivory ◽  
Bulb Dormancy ◽  
Random Occurrence ◽  
Northern Range Limit

We investigated patterns of dormancy and reproduction over time in two long-lived grassland perennial species, Calochortus lyallii Baker and Calochortus macrocarpus Dougl. Three populations of each species were monitored over 5 years near Osoyoos, British Columbia, at the northern range limit for C. lyallii and near the elevational limit for C. macrocarpus. On average, C. macrocarpus bulbs flowered less frequently but had higher fruit set and produced more seeds per capsule than C. lyallii bulbs. In C. lyallii, low fruit set was related primarily to premature abortion of buds and flowers, whereas the potentially higher seed production of C. macrocarpus was largely offset by deer herbivory. Prolonged bulb dormancy was common in both species, with up to 18% of C. lyallii and 26% of C. macro carpus bulbs dormant in a given population and year. Dormancy episodes typically lasted a single year, although episodes as long as 4 years were also recorded. In both species dormancy was synchronized across sites, implying that it was not a random occurrence within populations but a response to the same external factor(s). Population surveys involving geophytes should consider the possibility that the visible population is not necessarily indicative of actual population size, and that a population may still be extant even when no individuals are observed.Key words: Calochortus, bulb dormancy, herbivory, range limits, geophyte, population persistence.

scholarly journals Frontier mutualism: coevolutionary patterns at the northern range limit of the leaf-cutter ant–fungus symbiosis

2011 ◽  
Vol 278 (1721) ◽  
pp. 3050-3059 ◽  
Author(s):  
Ulrich G. Mueller ◽  
Alexander S. Mikheyev ◽  
Scott E. Solomon ◽  
Michael Cooper
Keyword(s):  
Range Limits ◽  
Peripheral Populations ◽  
Range Limit ◽  
Long Distance ◽  
Dispersal Barrier ◽  
The Andes ◽  
Genetic Patterns ◽  
Northern Range Limit ◽  
Traditional Assumption ◽  
Ant Fungus

Tropical leaf-cutter ants cultivate the fungus Attamyces bromatificus in a many-to-one, diffuse coevolutionary relationship where ant and fungal partners re-associate frequently over time. To evaluate whether ant– Attamyces coevolution is more specific (tighter) in peripheral populations, we characterized the host-specificities of Attamyces genotypes at their northern, subtropical range limits (southern USA, Mexico and Cuba). Population-genetic patterns of northern Attamyces reveal features that have so far not been observed in the diffusely coevolving, tropical ant– Attamyces associations. These unique features include (i) cases of one-to-one ant– Attamyces specialization that tighten coevolution at the northern frontier; (ii) distributions of genetically identical Attamyces clones over large areas (up to 81 000 km 2 , approx. the area of Ireland, Austria or Panama); (iii) admixture rates between Attamyces lineages that appear lower in northern than in tropical populations; and (iv) long-distance gene flow of Attamyces across a dispersal barrier for leaf-cutter ants (ocean between mainland North America and Cuba). The latter suggests that Attamyces fungi may occasionally disperse independently of the ants, contrary to the traditional assumption that Attamyces fungi depend entirely on leaf-cutter queens for dispersal. Peripheral populations in Argentina or at mid-elevation sites in the Andes may reveal additional regional variants in ant– Attamyces coevolution. Studies of such populations are most likely to inform models of coextinctions of obligate mutualistic partners that are doubly stressed by habitat marginality and by environmental change.

Extensions of the Known Northern Range Limits of Ocean Whitefish, Caulolatilus princeps, and California Halibut, Paralichthys californicus

1969 ◽  
Vol 26 (5) ◽  
pp. 1371-1372
Author(s):  
B. H. Pattie ◽  
C. S. Baker
Keyword(s):  
Range Limits ◽  
Range Limit ◽  
Paralichthys Californicus ◽  
California Halibut ◽  
Northern Range Limit

The known northern range limit of Caulolatilus princeps Jenyns is extended some 120 nautical miles further north and that of Paralichthys californicus Ayres nearly 100 miles further northwest.

Use it or Lose it: How Sexual Reproduction and Range Limits Interact in Decodon verticillatus

1969 ◽  
Author(s):  
Corrina Thomsen
Keyword(s):  
Sexual Reproduction ◽  
Aquatic Plant ◽  
Reproductive Traits ◽  
Arbitrary Point ◽  
Range Limits ◽  
Range Limit ◽  
Evolutionary Potential ◽  
Viable Population ◽  
Northern Range Limit ◽  
Physical Boundary

Why do most species live in a range that does not have a physical boundary? Mountains and oceans present obvious boundaries to range expansion, but most species’ range limits lack such obstacles, and end at a seemingly arbitrary point in space. These ranges generally represent a species’ niche, or the environments in which the species can grow, survive, and reproduce. Outside of this niche, individuals are poorly adapted to the environment and fail to create a viable population. Individuals at the range limit, however, exist in an environment that is similar to that outside of the range, and one might expect that they gradually adapt to these conditions and slowly expand their niche.  The fact that this does not commonly occur could indicate a failure to adapt in these individuals. Adaptation is largely driven by sexual reproduction, which recombines genes and can generate new genetic combinations. However, environmental conditions and population dynamics at the range limit could prevent sexual reproduction and cause populations to become asexual or clonal. Given enough time, this could lead to loss of reproductive traits, impacting the future evolutionary potential of range limit individuals. In this study, I investigate whether sexual reproduction is lost and the effect on key reproductive traits in the aquatic plant Decodon verticillatus at its Ontario northern range limit.

Variability in the parasitoid community associated with galls of Diplolepis variabilis (Hymenoptera: Cynipidae): a test of the distance decay hypothesis

2012 ◽  
Vol 144 (5) ◽  
pp. 635-644 ◽  
Author(s):  
Jordan A. Bannerman ◽  
Joseph D. Shorthouse ◽  
Jason Pither ◽  
Robert G. Lalonde
Keyword(s):  
Dispersal Limitation ◽  
The United States ◽  
Distance Decay ◽  
Range Limits ◽  
Range Limit ◽  
Community Similarity ◽  
Study Region ◽  
Northern Range Limit ◽  
Diverse Community ◽  
Gall Inducer

AbstractGalls of Diplolepis variabilis (Bassett) (Hymenoptera: Cynipidae) on their host plant Rosa woodsii Lindley (Rosaceae) support a diverse community of parasitoid and inquiline wasps that exploit the gall inducer and the gall itself. Here, we studied quantitative variation in local structure of the gall community in the Okanagan Valley of southern British Columbia, Canada, from the United States border north, to test the hypothesis that dispersal limitation would generate a distance decay in gall community similarity. We also explored gall community richness in relation to latitude, as the northern range limit of the gall inducer occurs within our study area. We found that gall communities exhibited strikingly similar composition across the study region, with most of the major inquilines and parasitoids present across the gall's range. However, the increased richness of rare parasitoid taxa near the northern range limits of D. variabilis generated a marginally significant positive relationship between gall community richness and latitude. Overall, our study suggests that dispersal constraints do not influence the composition of the Diplolepis Geoffroy gall community at regional scales, and that gall communities offer useful models for studying the association between community structure and range limits.

scholarly journals Is a species distribution model output reliable to test niche limitation at the northern range limit of a Pacific coastal dune plant?

2021 ◽  
Author(s):  
Jacqueline Grubel
Keyword(s):  
Species Distribution ◽  
Species Distribution Model ◽  
Range Limits ◽  
Distribution Model ◽  
Range Limit ◽  
Endemic Plant ◽  
Niche Limitation ◽  
Bioclimatic Variables ◽  
Northern Range Limit ◽  
Dune Plant

Jacqueline Grubel* and Christopher G. Eckert (Faculty Supporter) It is widely thought that the size, shape and location of a species’ geographical distribution are a spatial expression of its realized niche, and this assumption is central to evolutionary biology, biogeography and conservation. Yet, the hypothesis that geographical range limits are niche limits is not well supported by experimental translocations of species beyond their range limits. Beyond range populations often exhibit fitness high enough for self-replacement. In contrast, environmental niche models based on bioclimatic data often suggest a decline in habitat suitability beyond range limits, thereby supporting niche limitation. However very few studies have evaluated whether species distribution models (SDMs) accurately predict the viability of populations in nature, and scant results to date are not supportive. Long-term transplant with the short-lived, Pacific costal dune endemic plant Camissoniopsis cheiranthifolia (Onagraceae) suggest that populations are viable beyond the northern range limit over multiple generations. We constructed an SDM based on a large range-wide database of species records plus standard bioclimatic variables and substrate type. We also included sea surface temperature, which greatly modifies the climate of dune habitat. Preliminary results suggest that our SDM reliably predicts the fitness of experimental populations. However, both approaches indicate that something other than niche limitation enforces the northern range limit of this species. Results from this well-studied dune plant suggest that range limitation via constraints on dispersal may play an important role in limiting northern range expansion.

Green Turtles Nesting at Their Northern Range Limit in the United States Represent a Distinct Subpopulation

2018 ◽  
Vol 17 (2) ◽  
pp. 314 ◽  
Author(s):  
Brian M. Shamblin ◽  
Matthew H. Godfrey ◽  
S. Michelle Pate ◽  
William P. Thompson ◽  
Hope Sutton ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Range Limit ◽  
Green Turtles ◽  
Distinct Subpopulation ◽  
Northern Range Limit

Breeding behaviour of ectotherms at high latitudes: the case of the natterjack toad Epidalea calamita at its northern range limit

Behaviour ◽  
2021 ◽  
pp. 1-20
Author(s):  
Linda Saare ◽  
Riinu Rannap
Keyword(s):  
Climatic Conditions ◽  
Energetic Cost ◽  
Breeding Period ◽  
High Latitudes ◽  
Range Limit ◽  
Photo Identification ◽  
Breeding Behaviour ◽  
Risk Of Predation ◽  
Increased Risk ◽  
Northern Range Limit

Abstract We explored the breeding behaviour of a threatened amphibian, the natterjack toad, at its northern range limit in Estonia, to determine the extent to which reproduction is affected by harsh and unstable climatic conditions. Using photo identification of specimens, we found that in optimal weather conditions males formed three breeding cohorts, while in adverse conditions only a single cohort occurred and under extreme conditions reproduction was skipped entirely. During the extended breeding season, larger males participated in reproduction throughout the breeding period, while smaller males appeared in later cohorts. Breeding success was related to the calling effort of a male, where larger males had greater mating success than smaller ones. We found that the natterjack toad males exhibit significant plasticity in reproductive behaviour at the northern range limit, which, given the energetic cost of reproduction and the increased risk of predation, allows them to increase their fitness at high latitudes.

Living on the edge: Fig tree phenology at the northern range limit of monoecious Ficus in China

2014 ◽  
Vol 57 ◽  
pp. 135-141 ◽  
Author(s):  
Lu-Shui Zhang ◽  
Stephen G. Compton ◽  
Hui Xiao ◽  
Qian Lu ◽  
Yan Chen
Keyword(s):  
Range Limit ◽  
Tree Phenology ◽  
Northern Range Limit ◽  
Fig Tree
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