Reproductive Adults Research Articles

Long-Term Trends in the Occurrence of Disseminated Neoplasia in a Population of Mya arenaria (Softshell Clam) from a New Hampshire Estuary

Mya arenaria (Softshell Clam) is an important recreational and commercial bivalve in coastal New England, the mid-Atlantic, and elsewhere. The Softshell Clam is a filter feeder that provides a trophic link between planktonic food items and benthic predators. We quantified annual trends of disseminated neoplasia in Softshell Clams in the Hampton–Seabrook estuary in New Hampshire using logistic regression from 3975 individuals collected from 2002 to 2018. There was a negative trend in the incidence of Softshell Clams with non-detectable amounts of neoplastic cells, there was no significant trend in the incidence of stage 1 neoplasia (1–25% neoplastic cells), positive trends in the incidences of stages 2 and 3 (26–50% and 51–75% neoplastic cells), and no significant trends in incidence of stage 4 (76–100% neoplastic cells). The significant changes in neoplasia development suggest that the incidence of the disease is increasing. The lack of a significant trend in the terminal stage 4 neoplasia may be due to the short duration of this stage prior to death. Probabilities of acquiring stages 2 and 3 neoplasia in 2018 were 0.19 and 0.12, respectively. The mean length of Softshell Clams with stage 4 neoplasia was 66.7 mm (min–max = 53.2–78.1 mm), which indicates that terminal neoplasia occurs primarily in reproductive adults. The presence of advanced stages of the disease in sexually mature individuals can reduce the reproductive potential of that population.

Steroid hormone pathways coordinate developmental diapause and olfactory remodeling in Pristionchus pacificus.

Developmental and behavioral plasticity allow animals to prioritize alternative genetic programs during fluctuating environments. Behavioral remodeling may be acute in animals that interact with host organisms, since reproductive adults and the developmentally arrested larvae often have different ethological needs for chemical stimuli. To understand the genes that coordinate the development and host-seeking behavior, we used the entomophilic nematode Pristionchus pacificus to characterize dauer-constitutive mutants (Daf-c) that inappropriately enter developmental diapause to become dauer larvae. We found two Daf-c loci with dauer-constitutive and cuticle exsheathment phenotypes that can be rescued by the feeding of Δ7-dafachronic acid, and that are dependent on the conserved canonical steroid hormone receptor Ppa-DAF-12. Specifically at one locus, deletions in the sole hydroxysteroid dehydrogenase (HSD) in P. pacificus resulted in Daf-c phenotypes. Ppa-hsd-2 is expressed in the canal-associated neurons (CANs) and excretory cells whose homologous cells in Caenorhabditis elegans are not known to be involved in the dauer decision. While in wildtype only dauer larvae are attracted to host odors, hsd-2 mutant adults show enhanced attraction to the host beetle pheromone, along with ectopic activation of a marker for putative olfactory neurons, Ppa-odr-3. Surprisingly, this enhanced odor attraction acts independently of the Δ7-DA/DAF-12 module, suggesting that Ppa-HSD-2 may be responsible for several steroid hormone products involved in coordinating the dauer decision and host-seeking behavior in P. pacificus.

Depicting the mating system and patterns of contemporary pollen flow in trees of the genus Anadenanthera (Fabaceae).

Anadenanthera (Fabaceae) is endemic to the Neotropics and consists of two tree species: A. colubrina (Vell.) Brenan and A. peregrina (L.) Speg. This study examined the mating system and contemporary gene flow of A. colubrina (Acol) and A. peregrina (Aper) in a highly fragmented area of the Atlantic Forest to provide valuable information that informs conservation strategies. Reproductive adults from forest remnants [nA. colubrina = 30 (2.7 ha), nA. peregrina = 55 (4.0 ha)] and progeny-arrays (nA. colubrina = 322, nA. peregrina = 300) were genotyped for seven nuclear microsatellite markers. Mating system analyses revealed that A. colubrina is a mixed mating species (tm = 0.619) while A. peregrina is a predominantly outcrossing species (tm = 0.905). For both Anadenanthera species, high indices of biparental inbreeding were observed (Acol = 0.159, Aper = 0.216), resulting in low effective pollination neighborhood sizes. Categorical paternity analysis revealed different scales of pollen dispersal distance: the majority of crossings occurring locally (i.e., between nearby trees within the same population), with moderate pollen dispersal coming from outside the forest fragments boundaries (Acolmp = 30%, Apermp = 35%). Nevertheless, pollen immigration from trees outside the populations for both species suggests that the populations are not reproductively isolated. This study highlights the importance of evaluating both mating system and contemporary gene flow for a better understanding of the biology of Anadenanthera species. This information should be considered to ensure the effective conservation and management practices of these plant species.

Effect of seed collection on the structure and dynamics of wild populations of Dioon edule (Zamiaceae)1,2

The near-threatened cycad Dioon edule (Zamiaceae) is distributed in the Sierra Madre Oriental in Mexico. An important ancestral cultural tradition in the region is seed collecting by indigenous and nonindigenous communities to prepare food up to more than six times a year, without the regulation of the frequency of collection and the number of seeds extracted. In natural conditions, 90% of plants die in the early stages of their life cycle, because of natural and anthropic factors. The objectives of this study were to assess the structure and dynamics of populations where seeds are frequently collected and compare with populations where seed collection does not occur to determine the effect. According to our study of demography, seed collection affects the dynamics and structure of the populations by altering the male:female ratio of plants. This could affect the continuity of the species in the long term, since the number of seeds available for incorporation into the population with the possibility of becoming reproductive adults decreases. It is suggested to design plans that allow the sustainable use of this resource and, in turn, allow the conservation of the traditional knowledge of the Xi'iuy indigenous group. Management of sustainable seed collection could be achieved by rotating collection in stands over a minimum period of 15 years, which is long enough to recover the minimum seed production.

Embryonic shell shape as an early indicator of pollution in marine gastropods

Gastropods shell shape has been proposed as a good indicator of environmental changes while geometric morphometric (GM) is a powerful tool to detect such changes. Shell shape pattern in adults of the marine gastropod Buccinanops deformis was proved to be correlated with imposex incidence and maritime traffic in populations of Patagonia. We explore through GM the shell shape variation of B. deformis intracapsular embryos in pre-hatching stages of development, in two populations with contrasting maritime traffic and imposex incidence. Embryonic shell shape from polluted and unpolluted areas was significantly different in apex, lateral, aperture and siphonal channel. The same shell shape pattern was observed previously in B. deformis adult specimens. Our results demonstrate that the embryonic shell shape is an early biomarker that could be used as a tool to detect the response to environmental pollution studying abundant egg capsules laid in the field but protecting reproductive adults.

Sensitivity of sand lance to shifting prey and hydrography indicates forthcoming change to the northeast US shelf forage fish complex

AbstractNorthern sand lance (Ammodytes dubius) and Atlantic herring (Clupea harengus) represent the dominant lipid-rich forage fish species throughout the Northeast US shelf and are critical prey for numerous top predators. However, unlike Atlantic herring, there is little research on sand lance or information about drivers of their abundance. We use intra-annual measurements of sand lance diet, growth, and condition to explain annual variability in sand lance abundance on the Northeast US Shelf. Our observations indicate that northern sand lance feed, grow, and accumulate lipids in the late winter through summer, predominantly consuming the copepod Calanus finmarchicus. Sand lance then cease feeding, utilize lipids, and begin gonad development in the fall. We show that the abundance of C. finmarchicus influences sand lance parental condition and recruitment. Atlantic herring can mute this effect through intra-guild predation. Hydrography further impacts sand lance abundance as increases in warm slope water decrease overwinter survival of reproductive adults. The predicted changes to these drivers indicate that sand lance will no longer be able to fill the role of lipid-rich forage during times of low Atlantic herring abundance—changing the Northeast US shelf forage fish complex by the end of the century.

Dauer Development Modulates Olfactory Behavior.

Reproductive adults and developmentally arrested larvae often occupy different ecological niches and thus are expected to respond differently to environmental stimuli. To understand the genes that coordinate dauer development and olfactory behavior, we examined adult and dauer C. elegans in wild-type and dauer constitutive mutants (Daf-c). We found all dauers showed decreased attraction to all three odorants tested compared to adults, with daf-7 dauer larva (DL) exhibiting a concentration-dependent preference shift towards isoamyl alcohol, suggesting that the TGF-ß pathway is involved in both dauer regulation and dauer-specific odortaxis.

The role of parental care in the establishment of the offspring digestive tract microbiome in Nicrophorus defodiens

Parental care has evolved to increase offspring fitness. Burying beetles, which breed on small vertebrate carcasses, engage in extensive parental care, including prehatch carcass preservation using oral and anal secretions and direct posthatch care by regurgitating food for offspring. Aspects of parental care, such as regurgitation, may also act as a means of transmitting beneficial microbes to offspring. To explore the contributions of parental care to microbial transmission, we used Illumina high-throughput sequencing of the 16S rRNA gene to characterize bacterial communities found on prepared carcasses and in the digestive tracts of wild-caught and laboratory-reared adults and in the digestive tracts of larvae that either received or did not receive parental care. We found that the digestive tract bacterial communities of larvae receiving parental care were similar to those of their parents, whereas digestive tract bacterial communities of larvae not receiving parental care were dissimilar to those of their parents. All larval digestive tract bacterial communities were dissimilar from those found on prepared carcasses. Furthermore, we found that the digestive tract bacterial communities did not differ significantly between wild-caught nonreproductive adults and F1 and F2 laboratory-reared nonreproductive adults or between laboratory-reared nonreproductive and reproductive adults. While previous work showed that a prepared carcass may serve to inoculate some larval digestive tract bacteria, the results of the present study suggest that this role may be relatively minor and that parental care is crucial in shaping the gut microbiome of offspring, with aspects of this care, such as parental regurgitation, likely being an important component of the transmission process. Furthermore, as wild-reared and laboratory-reared adults did not vary significantly in their digestive tract bacterial communities, our findings suggest that gut microbiome transmittance within our Nicrophorus defodiens model is likely germane to the natural system. • Parental care plays a role in transmitting gut bacteria to larvae in Nicrophorus defodiens. • Larval gut bacterial communities differ when receiving parental care or not. • Core gut bacteria persist throughout the N. defodiens life cycle. • Reproductive and nonreproductive adults have similar gut bacterial communities.

Carnauba demography: analysis of the spatial pattern

Studies of spatial patterns are important in the elaboration of hypotheses on the dynamics of plant populations. In this context, the research aimed to investigate the spatial pattern between different life stages (regenerating, young and adult) of the Copernicia prunifera an endemic palm from the Brazilian semiarid. The study was carried out on a plot present in a remaining area of the Caatinga biome. The second-order neighboring function (NDF) was used to determine the degree of aggregation (univariate analysis) and if there is an association between the life stages (bivariate analysis). The NDF spatial pattern analysis for all C. prunifera individuals showed significant levels of aggregation up to a radius of 6 m and random pattern at higher distances. The bivariate analysis resulted in aggregation with a radius of 8 m between regenerating individuals and reproductive adults, indicating spatial association. Factors such as limited seed dispersal around the maternal plant and intra-species competition in the early stages of C. prunifera life are possibly responsible for the changes observed in the spatial pattern between the life stages of the species.

Does sex ratio bias and sexual dimorphism occur in Lindera benzoin L. (Lauraceae) prior to fruit production? 1

Secondary (flowering) sex ratio of a wild population of the dioecious woody shrub Lindera benzoin (spicebush) in Maryland has been persistently female biased over a time span of ∼ 17 years. Female-biased secondary sex ratios are relatively uncommon in dioecious woody plants, and are not readily explained by differential costs of reproduction, which are generally higher in females. In fact, prior studies of reproductive adults in L. benzoin populations have shown higher growth rates in males. This leads to questions concerning the source of female-biased sex ratios in some populations. Using seeds collected from 15 maternal plants at the Maryland site in 2013, a potted plant study was conducted from 2014–2020 in which periodic flowering censuses were taken, and plant size parameters were recorded. This study improves upon an analogous common garden study conducted under highly competitive conditions that induced considerable preflowering mortality. In the current study, plants were grown in pots to eliminate root competition and in a loose array to minimize shoot competition; mortality was thus kept to ∼ 1% after seed germination. Like the source population, genet sex ratios in the current study were significantly female-biased, partly due to a trend toward female-biased sex ratios in the offspring of a number of maternal plants. Estimates of plant size were generally higher for females in 2018, just prior to the onset of significant fruit production, supporting earlier results suggesting that females may compensate for differential costs of reproduction that can manifest after fruiting begins. Even in the absence of biased primary sex ratios, formation of female bias in wild populations could involve development of a relatively larger size in the pre-fruiting stage that gives females a temporary advantage over males. This could lead to relatively greater survival and/or earlier flowering of female plants in the early stages of population establishment, and could thus explain observed patterns of sex ratio bias.

Disentangling the multiple effects of stream drying and riparian canopy cover on the trophic ecology of a highly threatened fish

Abstract Understanding risks to aquatic systems posed by changing drought regimes is particularly important for the conservation of already threatened taxa. However, little is known about how local environmental conditions, especially those in heavily human‐influenced situations, interact with regional shifts such as droughts to alter realised impacts on aquatic communities, including threatened top predators. Here, we investigated the combined effects of stream drying intensity and riparian canopy cover on the trophic interactions of critically endangered kōwaro, or Canterbury mudfish (Neochanna burrowsius) in an agricultural area of New Zealand. Fish populations and their potential prey, both terrestrial and aquatic, as well as environmental variables, including riparian canopy cover and drying measured with stage loggers, were sampled over eight visits to 24 sites spanning orthogonal drying and canopy gradients. Stable isotope ratios, 13C/12C and 15N/14N, were used to investigate trophic links between mudfish and their terrestrial and aquatic prey across these gradients. When non‐native willows (predominantly Salix fragilis) dominated the riparian canopy, increased tree cover led to elevated drying intensity, probably driven by their relatively high water demands compared to other trees. However, in the absence of willows, canopy cover had no effect on drying intensity. Although this was the only direct link between these two environmental factors, they had opposing effects on kōwaro populations, which will be important for management under drought. Increased drying intensity contributed to elevated abundance of microcrustacea and aquatic Diptera larvae, and an increase in the relative abundance of kōwaro juveniles. However, drying‐affected kōwaro populations also had fewer large reproductive adults and elevated δ15N values, probably driven by physiological limitations and an increase in kōwaro cannibalism, respectively. By comparison, increased canopy cover enhanced input of terrestrial invertebrates, a food resource for larger kōwaro, leading to elevated kōwaro δ13C values, no effects on δ15N values, and higher relative abundance of large kōwaro in shaded streams compared to unshaded streams. Thus, the riparian canopy cover was able to offset some of the effects of drying. Overall, we found no interactions between drying intensity and canopy cover affecting kōwaro. However, their opposing effect highlights the important role local conditions such as riparian canopies play on aquatic communities and their potential role as a restoration tool to mitigate the effects of large‐scale shifts such as drought.

Demographics of the semi-slug Parmarion martensi, an intermediate host for Angiostrongylus cantonensis in Hawai'i, during laboratory rearing.

The semi-slug, Parmarion martensi, is an intermediate host of the zoonotic nematode, Angiostrongylus cantonensis, the aetiological agent of neuroangiostrongyliasis or rat lungworm disease in humans. Rearing methods were developed for P. martensi to facilitate studies on nematode transmission and control. Parmarion martensi exhibited high survivorship when reared on a diet of dog food and fresh fruits and vegetables in temperature-controlled cabinets at 21.4°C, 98% relative humidity and 12:12 L:D cycle. Rearing containers were lined with moist paper towels for substrate and plastic pots were provided for hiding/resting and egg-laying. Under these conditions, time to first reproduction was 165.3 ± 12.3 days, fecundity was approximately 34.5 ± 7.8 eggs per adult, and hatch rate was 52.7 ± 3.2%. Survivorship post egg hatch was 86.2 ± 2.9% at 30 days (neonates had a mortality rate of about 14%) and 99% thereafter for up to a year. The demographics of laboratory-reared and wild-caught P. martensi were similar except for the weight of reproductive adults, which was significantly higher in laboratory-reared adults (4.0 ± 0.2 g) than in field-collected adults (1.5 ± 0.1 g).

Using genomics to design and evaluate the performance of underwater forest restoration

Abstract Restoration is an emerging intervention to reverse the degradation and loss of marine habitat‐formers and the ecosystem services they underpin. Current best practice seeks to restore populations by transplanting donor individuals chosen to replicate genetic diversity and structure of extant, nearby populations. However, genetic characteristics are rarely empirically examined across generations, despite their potential role in influencing restoration success. We used genomics to design a restoration program for lost underwater forests of Phyllospora comosa, a dominant forest‐forming macroalga that went locally extinct from reefs off Sydney, Australia. Population genetic diversity and structure of nearby extant populations informed choice of donor sites. We tested whether donor provenance influenced adult transplant survival, condition (via metrics of epibiosis) and the genetic characteristics of recruits at restoration sites. Extant populations of Phyllospora within a 100‐km radius of Sydney comprised three distinct genetic clusters with similar levels of genetic diversity. We transplanted reproductive adults from two of these sites, with the aim of restoring five Phyllospora forests with levels of genetic structure and diversity similar to donor populations. Donor provenance influenced survival and condition of transplanted adults and recruitment levels varied significantly among restoration sites. Yet, recruitment was rapid and genetic diversity and structure of the F1 generation resembled extant populations. This likely occurred because transplanted individuals reproduced synchronously and rapidly post‐transplantation, prior to mortality of adult donor transplants. Synthesis and applications. As restoration and the need to ‘future‐proof’ marine ecosystems increase globally, it will be critical to understand and harness the role of donor provenance, genetic diversity and structure in restoration success. By incorporating ecological and genomic data into restoration design and assessment, this study demonstrates that evidence‐based selection of macroalgal donors can result in F1 generation recruits with similar levels of genetic diversity and structure as extant populations, despite an effect of provenance on transplant survival and condition. This study also highlights the need for ongoing refinement of transplantation techniques to ensure future recruitment success.

Post-dispersal factors influence recruitment patterns but do not override the importance of seed limitation in populations of a native thistle.

Whether plant populations are limited by seed or microsite availability is a long-standing debate. However, since both can be important, increasing emphasis is placed on disentangling their relative importance and how they vary through space and time. Although uncommon, seed addition studies that include multiple levels of seed augmentation, and follow plants through to the adult stage, are critical to achieving this goal. Such data are also vital to understanding when biotic pressures, such as herbivory, influence plant abundance. In this study, we experimentally added seeds of a native thistle, Cirsium canescens, at four augmentation densities to plots at two long-term study sites and quantified densities of seedlings and reproductive adults over 9years. Recruitment to both seedling and adult stages was strongly seed-limited at both sites; however, the relative strength of seed limitation decreased with plant age. Fitting alternative recruitment functions to our data indicated that post-dispersal mortality factors were important as well. Strong density-dependent mortality limited recruitment at one site, while density-independent limitation predominated at the other. Overall, our experimental seed addition demonstrates that the environment at these sites remains suitable for C. canescens survival to reproduction and that seed availability limits adult densities. The results thus provide support for the hypothesis that seed losses due to the invasive weevil, Rhinocyllus conicus, rather than shifting microsite conditions, are driving C. canescens population declines. Shifts in the importance of density-dependent recruitment limitation between sites highlights that alternate strategies may be necessary to recover plant populations at different locations.

Seedling maturation drives spatial variability in demographic dynamics of an invader with multiple introductions: insights from an LTRE analysis

Multiple introductions are hypothesized to facilitate the success of invasive plant species, because they can result in novel genotypes through intraspecific hybridization potentially increasing the ability to adapt to the novel environment. In this study, we address the question of how the demography of an invader with multiple introductions and intraspecific hybridization varies across sites. This was done by modeling the population dynamics of Brazilian pepper, Schinus terebinthifolia Raddi (Anacardiaceae), a shrub native to Brazil, Paraguay and Argentina that has invaded the global subtropics and was introduced to Florida on two separate occasions. This species exhibits variability in growth form such that vertical and lateral growth are not strongly associated. Our demographic field work took place at six sites spanning the introduced range in Florida and differing in introduction history. For each site we constructed integral projection models where the probabilities of survival, growth and reproduction were modeled as functions of two different metrics of size, the continuous variables diameter and height, metrics of vertical and lateral growth, respectively. We performed a Life Table Response Experiment analysis to decompose the effects of variation among sites in vital rates on the population dynamics of S. terebinthifolia. We found that spatial variation in population dynamics was driven primarily by site-level differences in the maturation of seedlings into reproductive adults. The survival and growth of the largest individuals had the highest elasticity, suggesting that management actions capable of decreasing these vital rates would have the greatest effect on reducing the population growth rate.

AMPHIBIAN DISTRIBUTION IN THE GEORGIA SEA ISLANDS: IMPLICATIONS FROM THE PAST AND FOR THE FUTURE

We summarized amphibian distributions for 12 coastal islands in Georgia, USA. Occurrence among islands was correlated with life history traits, habitats, island size, distance to other islands, and island geological age. Species’ distributions were determined from published literature. Island sizes and vegetation types were derived from 2011 Georgia Department of Natural Resources habitat maps, which included both federal and state vegetation classification systems. Species occurring on more islands tended to have greater total reproductive output (i.e., life span >4 years, and annual egg production >1,000 eggs) and adults had tolerance of brackish environs. Larger islands had great­er area of freshwater wetlands, predominantly short hydroperiod (<6 months). Species tied to long hydroperiod wetlands (>6 months) were more restricted in their distribution across islands. Overall, larger islands supported more species, but the correlation was weaker for geologically younger Ho­locene islands (age <11,000 years). While Euclidean distance between islands does not necessarily preclude inter-island dispersal, inhospitable habitat for amphibians (brackish tidal marshes and creeks interspersed with wide rivers) suggests that inter-island dispersal is very limited. The paucity of recent occurrence data for amphibians in this dynamic coastal region, let alone standardized annual moni­toring data, hinders efforts to model species’ vulnerability in a region susceptible to sea level rise and development pressure. The most common survey method, standardized amphibian vocal surveys, will detect Anuran reproductive efforts, but is unlikely to ascertain if breeding was successful or to detect salamanders. While it will not replace actual population data, consideration of critical life-history traits and breeding habitat availability can be used to direct management to support long-term species per­sistence in changing environs. Even common amphibians in coastal conservation areas of Georgia are vulnerable to increasing population isolation caused by unsuitable habitat.

Mass displacement of Korean clawed salamanders (Onychodactylus koreanus) and the threat of road-kill

Little is known about the ecology of the Korean clawed salamander (Onychodactylus koreanus) but populations are declining due to human activities. We surveyed a mountainside road in the Republic of Korea and recorded the sex and life history stage of the salamanders crossing the road. Our results present the first evidence of mass movement in this species. We also show that road-kill is greater than estimated in previous studies. The males observed had fleshy hind-limb extensions and all females except one were gravid, indicating they were in reproductive condition and that mass movement of this species is probably linked to seasonal conditions and reproduction. Consequently, we argue that road kill may have a large impact on this species by eliminating reproductive adults. We call for road-kill mitigation measures on mountainside roads and further research into the migration patterns of this species.

Embryo integrity regulates maternal proteostasis and stress resilience.

The proteostasis network is regulated by transcellular communication to promote health and fitness in metazoans. In Caenorhabditis elegans, signals from the germline initiate the decline of proteostasis and repression of cell stress responses at reproductive maturity, indicating that commitment to reproduction is detrimental to somatic health. Here we show that proteostasis and stress resilience are also regulated by embryo-to-mother communication in reproductive adults. To identify genes that act directly in the reproductive system to regulate somatic proteostasis, we performed a tissue targeted genetic screen for germline modifiers of polyglutamine aggregation in muscle cells. We found that inhibiting the formation of the extracellular vitelline layer of the fertilized embryo inside the uterus suppresses aggregation, improves stress resilience in an HSF-1-dependent manner, and restores the heat-shock response in the somatic tissues of the parent. This pathway relies on DAF-16/FOXO activation in vulval tissues to maintain stress resilience in the mother, suggesting that the integrity of the embryo is monitored by the vulva to detect damage and initiate an organismal protective response. Our findings reveal a previously undescribed transcellular pathway that links the integrity of the developing progeny to proteostasis regulation in the parent.

FLOWERING CYCLE OF CHUSQUEA MOLLIS L.G. CLARK (MAGNIFOLIAE, CHUSQUEINAE, BAMBUSAE) IN THE VENEZUELAN ANDES

Flowering cycles are poorly understood in the majority of woody bamboos, since their frequency and duration may vary according their growth-form and distribution across latitude and altitude ranges. Tropical Andean bamboos are known for combining gregarious (asynchronic) and asynchronic flowering events; the main objective of this study was to determine the flowering pattern of Chusquea mollis Swallen) L.G. Clark (= Neurolepis mollis Swallen), a monocarpic, native bamboo that grows in the subparamos and paramos of Venezuela and Colombia. The chronology of flowering events of this species was based on the revision of herbarium specimens, online databases and the occurrence of flowering events in two populations of the Cordillera de Mérida, Venezuela. Taking in account that age diversity may also contribute to identify flowering patterns in bamboo populations, we performed a survey of a single population located in the Páramo La Aguada. Our results suggest that C. mollis combines gregarious and asynchronic flowering cycles, after a relatively short vegetative period (5-7 years). The census conducted in a single population of La Aguada revealed the co-existence of plantlets, juvenile plants, vegetative, reproductive and post-reproductive adults, of which the juvenile were the most numerous group.

Benefits of Head‐starting for Blanding's Turtle Size Distributions and Recruitment

ABSTRACTHead‐starting is a widely used turtle conservation measure but its effectiveness is incompletely known. We evaluated the success of 2 long‐term Blanding's turtle (Emydoidea blandingii) head‐starting programs in northeastern Illinois, USA, focusing on the effect that head‐starting has on turtle population body‐size distributions and whether head‐started turtles are successfully recruited as reproductive adults. From 1994 to 2017, we collected and incubated eggs from wild females and reared hatchlings for release back into 2 source populations in DuPage and Lake counties, Illinois. Releases occurred annually for 21‐ and 11‐year spans (~1,400 and 800 releases, respectively). We found that head‐starting resulted in significant shifts in Blanding's turtle population body‐size distributions. Prior to intervention, size distributions were strongly skewed toward large adults at both sites, a pattern sometimes interpreted as arising from elevated egg and hatchling mortality and a lack of juvenile recruitment. Currently, population body‐size distributions include a wide range of juvenile and adult size turtles. Importantly, head‐starts have begun reproducing in the 21‐year program and are approaching adult size in the 11‐year program. Blanding's turtle head‐starting shows promise for increasing recruitment in existing populations while threat mitigation is implemented. © 2020 The Wildlife Society.