scholarly journals Snakes on an African plain: the radiation of Crotaphopeltis and Philothamnus into open habitat (Serpentes: Colubridae)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11728
Author(s):  
Hanlie M. Engelbrecht ◽  
William R. Branch ◽  
Krystal A. Tolley
Keyword(s):  
Habitat Type ◽  
Evolutionary Analysis ◽  
Ancestral State ◽  
Vegetation Shifts ◽  
Species Association ◽  
Open Habitat ◽  
Specialist Species ◽  
Habitat Generalist ◽  
Habitat Specialist Species ◽  
Lineage Diversification

Background The African continent is comprised of several different biomes, although savanna is the most prevalent. The current heterogeneous landscape was formed through long-term vegetation shifts as a result of the global cooling trend since the Oligocene epoch. The overwhelming trend was a shift from primarily forest, to primarily savanna. As such, faunal groups that emerged during the Paleogene/Neogene period and have species distributed in both forest and savanna habitat should show a genetic signature of the possible evolutionary impact of these biome developments. Crotaphopeltis and Philothamnus (Colubridae) are excellent taxa to investigate the evolutionary impact of these biome developments on widespread African colubrid snakes, and whether timing and patterns of radiation are synchronous with biome reorganisation. Methods A phylogenetic framework was used to investigate timing of lineage diversification. Phylogenetic analysis included both genera as well as other Colubridae to construct a temporal framework in order to estimate radiation times for Crotaphopeltis and Philothamnus. Lineage diversification was estimated in Bayesian Evolutionary Analysis Sampling Trees (BEAST), using two mitochondrial markers (cyt–b, ND4), one nuclear marker (c–mos), and incorporating one fossil and two biogeographical calibration points. Vegetation layers were used to classify and confirm species association with broad biome types (‘closed’ = forest, ‘open’ = savanna/other), and the ancestral habitat state for each genus was estimated. Results Philothamnus showed an ancestral state of closed habitat, but the ancestral habitat type for Crotaphopeltis was equivocal. Both genera showed similar timing of lineage diversification diverging from their sister genera during the Oligocene/Miocene transition (ca. 25 Mya), with subsequent species radiation in the Mid-Miocene. Philothamnus appeared to have undergone allopatric speciation during Mid-Miocene forest fragmentation. Habitat generalist and open habitat specialist species emerged as savanna became more prevalent, while at least two forest associated lineages within Crotaphopeltis moved into Afromontane forest habitat secondarily and independently. Discussion With similar diversification times, but contrasting ancestral habitat reconstructions, we show that these genera have responded very differently to the same broad biome shifts. Differences in biogeographical patterns for the two African colubrid genera is likely an effect of distinct life-history traits, such as the arboreous habits of Philothamnus compared to the terrestrial lifestyle of Crotaphopeltis.

Age-dependent colonization of urban habitats: a diachronic approach using carabid beetles and spiders

2013 ◽  
Vol 63 (3) ◽  
pp. 257-269 ◽  
Author(s):  
Marion Varet ◽  
Françoise Burel ◽  
Denis Lafage ◽  
Julien Pétillon
Keyword(s):  
Urban Areas ◽  
Time Lag ◽  
Ecosystem Dynamics ◽  
Carabid Beetles ◽  
Life History Trait ◽  
Generalist Species ◽  
High Dispersal ◽  
Specialist Species ◽  
Habitat Generalist ◽  
Habitat Specialist Species

Urbanization creates human disturbance that plays an important role in ecosystem dynamics. Most of the time, there is a time lag between disturbance and colonization. Opportunistic species with high dispersal power colonize first, while habitat specialist species with a lower power of dispersal colonize later; the communities change with time after disturbance. We hypothesize that, following the establishment of a new neighbourhood, arthropod communities will change from habitat generalists to specialists, and will be more similar to those of the adjacent countryside. We selected two groups of invertebrates often used as bioindicators, spiders and carabid beetles. The following parameters were estimated: assemblage composition, species richness, activity-density total and per life history trait (broad habitat preference). The field data were collected in 2010 within 3 towns located in France. Neighbourhoods of 10 and 30 years old were pair-matched in these towns and sampled using pitfall traps set randomly in hedgerows (120 traps in total). 2101 adult spiders belonging to 89 species were collected, whereas the 643 captured carabid beetles belonged to 24 species. We found no evidence of any significant change in carabid beetle and spider communities according to neighbourhood age. The assemblages were mainly composed of habitat generalist species. These results suggest that urban areas can be seen to be in continual state of disruption, and colonization of these areas is assumed to be relatively rapid (i.e., less than 10 years in our case study), although incomplete.

Contrasted influences of moon phases on the reproduction and movement patterns of four amphibian species inhabiting different habitats in central Italy

2014 ◽  
Vol 35 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Leonardo Vignoli ◽  
Manuela D’Amen ◽  
Francesca Della Rocca ◽  
Marco A. Bologna ◽  
Luca Luiselli
Keyword(s):  
Predation Risk ◽  
Central Italy ◽  
Habitat Type ◽  
Reproductive Phenology ◽  
Moon Phase ◽  
The Moon ◽  
Amphibian Species ◽  
Moon Phases ◽  
Fitness Effects ◽  
Open Habitat

Many studies have provided evidence that prey adjust their behaviour to adaptively balance the fitness effects of reproduction and predation risk. Nocturnal terrestrial animals should deal with a range of environmental conditions during the reproductive season at the breeding sites, including a variable amount of natural ambient light. High degrees of illumination are expected to minimize those behaviours that might increase the animal detection by predators. Therefore, under habitat variable brightness conditions and in different ecosystems, the above mentioned behaviours are expected to depend on the variation in predation risk. Although moon effects on amphibian biology have been recognized, the direction of this influence is rather controversial with evidences of both increased and depressed activity under full moon. We tested in four nocturnal amphibian species (Hyla intermedia, Rana dalmatina, Rana italica, Salamandrina perspicillata) the effects of different (i) light conditions and (ii) habitats (open land vs. dense forest) on the reproductive phenology. Our results showed that the effects of the lunar cycle on the study species are associated with the change in luminosity, and there is no evidence of an endogenous rhythm controlled by biological clocks. The habitat type conditioned the amphibian reproductive strategy in relation to moon phases. Open habitat breeders (e.g., ponds with no canopy cover) strongly avoided conditions with high brightness, whereas forest habitat breeders were apparently unaffected by the different moon phases. Indeed, for all the studied species no effects of the moon phase itself on the considered metrics were found. Rather, the considered amphibian species seem to be conditioned mainly by moonlight irrespective of the moon phase. The two anurans spawning in open habitat apparently adjust their oviposition timing by balancing the fitness effects of the risk to be detected by predators and the reproduction.

scholarly journals Forest-type specialization strongly predicts avian responses to tropical agriculture

2019 ◽  
Vol 286 (1913) ◽  
pp. 20191724
Author(s):  
Jacob B. Socolar ◽  
David S. Wilcove
Keyword(s):  
Forest Type ◽  
Soil Nutrient ◽  
Predictive Performance ◽  
Species Traits ◽  
Habitat Associations ◽  
Habitat Specialization ◽  
Habitat Features ◽  
Specialist Species ◽  
Habitat Specialist Species ◽  
Poor Soil

Species’ traits influence how populations respond to land-use change. However, even in well-characterized groups such as birds, widely studied traits explain only a modest proportion of the variance in response across species. Here, we show that associations with particular forest types strongly predict the sensitivity of forest-dwelling Amazonian birds to agriculture. Incorporating these fine-scale habitat associations into models of population response dramatically improves predictive performance and markedly outperforms the functional traits that commonly appear in similar analyses. Moreover, by identifying habitat features that support assemblages of unusually sensitive habitat-specialist species, our model furnishes straightforward conservation recommendations. In Amazonia, species that specialize on forests along a soil–nutrient gradient (i.e. both rich-soil specialists and poor-soil specialists) are exceptionally sensitive to agriculture, whereas species that specialize on floodplain forests are unusually insensitive. Thus, habitat specialization per se does not predict disturbance sensitivity, but particular habitat associations do. A focus on conserving specific habitats that harbour highly sensitive avifaunas (e.g. poor-soil forest) would protect a critically threatened component of regional biodiversity. We present a conceptual model to explain the divergent responses of habitat specialists in the different habitats, and we suggest that similar patterns and conservation opportunities probably exist for other taxa and regions.

The age of island-like habitats impacts habitat specialist species richness

Ecology ◽  
2012 ◽  
Vol 93 (5) ◽  
pp. 1106-1114 ◽  
Author(s):  
Michal Horsák ◽  
Michal Hájek ◽  
Daniel Spitale ◽  
Petra Hájková ◽  
Daniel Dítě ◽  
...  
Keyword(s):  
Species Richness ◽  
Habitat Specialist ◽  
Specialist Species ◽  
Habitat Specialist Species

scholarly journals Survival and habitat use of sympatric lagomorphs in bottomland hardwood forests

2018 ◽  
Vol 96 (7) ◽  
pp. 713-722 ◽  
Author(s):  
J.C. Crawford ◽  
C.K. Nielsen ◽  
E.M. Schauber
Keyword(s):  
Habitat Use ◽  
Forest Cover ◽  
Land Use Changes ◽  
Survival Rates ◽  
Basal Area ◽  
Interactive Effects ◽  
Bottomland Hardwood ◽  
Sylvilagus Floridanus ◽  
Specialist Species ◽  
Habitat Generalist

Lagomorphs are important consumers and prey in ecosystems worldwide, but have declined due to land use changes and habitat loss, and such losses may be exacerbated for specialist species. We compared survival and habitat use of two closely related lagomorphs, the swamp rabbit (Sylvilagus aquaticus (Bachman, 1837)), a bottomland hardwood (BLH) forest specialist, and the eastern cottontail (Sylvilagus floridanus (J. A. Allen, 1890)), a habitat generalist. We tested whether survival and habitat use differed between radio-collared swamp rabbits (n = 129) and eastern cottontails (n = 72) monitored during December 2009 – December 2013 in southern Illinois. We found interactive effects of species and season on survival rates: swamp rabbits had higher annual survival (0.37 ± 0.05 (estimate ± SE)) than did cottontails (0.20 ± 0.05), but this difference occurred primarily during the growing season. Swamp rabbits were located closer to watercourses in areas characterized by higher basal area and more mature BLH forest cover compared with eastern cottontails. Our results suggest that BLH forests may be marginal habitat for cottontails and indicate predation as the primary cause of mortality for both species. Swamp rabbits use of early-successional BLH forest suggests that restoration efforts have been successful. However, as specialists, swamp rabbits remain restricted to a narrow band of bottomlands near watercourses and may benefit from improved upland cover that serves as refugia from flooding.

A comparison of small mammal communities in two High-Andean Polylepis woodlands in Ecuador

2019 ◽  
Vol 11 (2) ◽  
Author(s):  
Reed Ojala-Barbour ◽  
Jorge Brito ◽  
William R. Teska
Keyword(s):  
Habitat Quality ◽  
Small Mammals ◽  
Habitat Heterogeneity ◽  
Habitat Degradation ◽  
Anthropogenic Pressures ◽  
Small Mammal Communities ◽  
Specialist Species ◽  
Habitat Generalist ◽  
High Elevations ◽  
Mammal Communities

Polylepis forest, historically widespread throughout high elevations of the central and northern Andes, now remain only in discontinuous small patches.  An expanding agricultural frontier, along with other anthropogenic pressures, imperils these remnants through further isolation and loss of habitat quality. Using two grids of live traps we compared the populations of small nonvolant mammals in an intact Polylepis woodland with one nearby that had been logged 50 years before. Our study is the first to examine the effects of habitat degradation and associated changes to vertical complexity and habitat heterogeneity on mammalian communities in Polylepis woodlands above 3500 m. The intact woodland had significantly more vertical complexity than the mid-successional woodland.  A total of 315 captures of 147 individuals of 9 species were sampled during an intensive trapping effort in 2010.  Trap success was especially high averaging 35.4 % and 28.1 % in the intact and mid-successional woodland, respectively.  Diversity and abundance of small mammals were greater in the intact woodland than the mid-successional site.  Forest specialist species were more abundant in the intact habitat; while Thomasomys paramorum, a habitat generalist, was dominant in both.  Habitat quality affected movement patterns of T. paramorum.  The results affirm a high diversity and density of small mammals in intact Polylepis woodland and indicate that the effects of habitat disturbance are species dependent.  We suggest that habitat specialists are more susceptible to loss of habitat heterogeneity and vertical complexity than habitat generalists. 

scholarly journals Striking between-population floral divergences in a habitat specialized plant

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253038
Author(s):  
Sumayya Abdul Rahim ◽  
Ullasa Kodandaramaiah ◽  
Aboli Kulkarni ◽  
Deepak Barua
Keyword(s):  
Common Garden ◽  
Habitat Specialization ◽  
Floral Traits ◽  
Sky Islands ◽  
Floral Variation ◽  
Floral Visitor ◽  
In The Wild ◽  
Specialist Species ◽  
Habitat Generalist ◽  
Common Garden Experiments

When the habitat occupied by a specialist species is patchily distributed, limited gene flow between the fragmented populations may allow population differentiation and eventual speciation. ‘Sky islands’—montane habitats that form terrestrial islands—have been shown to promote diversification in many taxa through this mechanism. We investigate floral variation in Impatiens lawii, a plant specialized on laterite rich rocky plateaus that form sky islands in the northern Western Ghats mountains of India. We focus on three plateaus separated from each other by ca. 7 to 17 km, and show that floral traits have diverged strongly between these populations. In contrast, floral traits have not diverged in the congeneric I. oppositifolia, which co-occurs with I. lawii in the plateaus, but is a habitat generalist that is also found in the intervening valleys. We conducted common garden experiments to test whether the differences in I. lawii are due to genetic differentiation or phenotypic plasticity. There were strong differences in floral morphology between experimental plants sourced from the three populations, and the relative divergences between population pairs mirrored that seen in the wild, indicating that the populations are genetically differentiated. Common garden experiments confirmed that there was no differentiation in I. oppositifolia. Field floral visitation surveys indicated that the observed differences in floral traits have consequences for I. lawii populations, by reducing the number of visitors and changing the relative abundance of different floral visitor groups. Our results highlight the role of habitat specialization in diversification, and corroborates the importance of sky islands as centres of diversification.

scholarly journals Framework Phylogeny, Evolution and Complex Diversification of Chinese Oaks

Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1024
Author(s):  
Jia Yang ◽  
Yu-Fan Guo ◽  
Xiao-Dan Chen ◽  
Xiao Zhang ◽  
Miao-Miao Ju ◽  
...  
Keyword(s):  
Sequence Data ◽  
Late Eocene ◽  
Tectonic Activity ◽  
Evolutionary Analysis ◽  
Species Radiation ◽  
Species Evolution ◽  
Phylogenetic Framework ◽  
Nuclear Loci ◽  
Lineage Diversification

Oaks (Quercus L.) are ideal models to assess patterns of plant diversity. We integrated the sequence data of five chloroplast and two nuclear loci from 50 Chinese oaks to explore the phylogenetic framework, evolution and diversification patterns of the Chinese oak’s lineage. The framework phylogeny strongly supports two subgenera Quercus and Cerris comprising four infrageneric sections Quercus, Cerris, Ilex and Cyclobalanopsis for the Chinese oaks. An evolutionary analysis suggests that the two subgenera probably split during the mid-Eocene, followed by intergroup divergence within the subgenus Cerris around the late Eocene. The initial diversification of sections in the subgenus Cerris was dated between the mid-Oligocene and the Oligocene–Miocene boundary, while a rapid species radiation in section Quercus started in the late Miocene. Diversification simulations indicate a potential evolutionary shift on section Quercus, while several phenotypic shifts likely occur among all sections. We found significant negative correlations between rates of the lineage diversification and phenotypic turnover, suggesting a complex interaction between the species evolution and morphological divergence in Chinese oaks. Our infrageneric phylogeny of Chinese oaks accords with the recently proposed classification of the genus Quercus. The results point to tectonic activity and climatic change during the Tertiary as possible drivers of evolution and diversification in the Chinese oak’s lineage.

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