Estimating the exposure of carnivorous plants to rapid climatic change

Author(s):  
Matthew C. Fitzpatrick ◽  
Aaron M. Ellison

Climatic change likely will exacerbate current threats to carnivorous plants. However, estimating the severity of climatic change is challenged by the unique ecology of carnivorous plants, including habitat specialization, dispersal limitation, small ranges, and small population sizes. We discuss and apply methods for modeling species distributions to overcome these challenges and quantify the vulnerability of carnivorous plants to rapid climatic change. Results suggest that climatic change will reduce habitat suitability for most carnivorous plants. Models also project increases in habitat suitability for many species, but the extent to which these increases may offset habitat losses will depend on whether individuals can disperse to and establish in newly suitable habitats outside of their current distribution. Reducing existing stressors and protecting habitats where numerous carnivorous plant species occur may ameliorate impacts of climatic change on this unique group of plants.

Author(s):  
Bartosz J. Płachno ◽  
Lyudmila E. Muravnik

We review the current knowledge of trap anatomy of carnivorous plants, with a focus on the diversity and structure of the glands that are used to attract, capture, kill and digest their prey and finally to absorb nutrients from carcasses of prey. These glands have diverse forms. Regardless of their structure and origin, they have the same functional units, but there are differences in subcellular mechanisms and adaptations for carnivory. We propose a new type of carnivorous plant trap—a ‘fecal traps—which has unique physiology, morphology, and anatomy for attracting the animals that are the source of excrement and also to retain and use it.


Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1604
Author(s):  
Sun Hee Hong ◽  
Yong Ho Lee ◽  
Gaeun Lee ◽  
Do-Hun Lee ◽  
Pradeep Adhikari

Predicting the distribution of invasive weeds under climate change is important for the early identification of areas that are susceptible to invasion and for the adoption of the best preventive measures. Here, we predicted the habitat suitability of 16 invasive weeds in response to climate change and land cover changes in South Korea using a maximum entropy modeling approach. Based on the predictions of the model, climate change is likely to increase habitat suitability. Currently, the area of moderately suitable and highly suitable habitats is estimated to be 8877.46 km2, and 990.29 km2, respectively, and these areas are expected to increase up to 496.52% by 2050 and 1439.65% by 2070 under the representative concentration pathways 4.5 scenario across the country. Although habitat suitability was estimated to be highest in the southern regions (<36° latitude), the central and northern regions are also predicted to have substantial increases in suitable habitat areas. Our study revealed that climate change would exacerbate the threat of northward weed invasions by shifting the climatic barriers of invasive weeds from the southern region. Thus, it is essential to initiate control and management strategies in the southern region to prevent further invasions into new areas.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5596 ◽  
Author(s):  
Qiongdao Zhang ◽  
Dong He ◽  
Hua Wu ◽  
Wei Shi ◽  
Cong Chen

Spiders are a functionally important taxon in forest ecosystems, but the determinants of arboreal spider beta diversity are poorly understood at the local scale. We examined spider assemblages in 324 European beech (Fagus sylvatica) trees of varying sizes across three forest stands in Würzburg (Germany) to disentangle the roles of tree architecture, spatial distance, and dispersal capacity on spider turnover across individual trees. A large proportion of tree pairs (66%) showed higher compositional dissimilarity in spider assemblages than expected by chance, suggesting prominent roles of habitat specialization and/or dispersal limitation. Trees with higher dissimilarity in DBH and canopy volume, and to a lesser extent in foliage cover, supported more dissimilar spider assemblages, suggesting that tree architecture comprised a relevant environmental gradient of sorting spider species. Variation partitioning revealed that 28.4% of the variation in beta diversity was jointly explained by tree architecture, spatial distance (measured by principal coordinates of neighbor matrices) and dispersal capacity (quantified by ballooning propensity). Among these, dispersal capacity accounted for a comparable proportion as spatial distance did (6.8% vs. 5.9%). Beta diversity did not significantly differ between high- and low-vagility groups, but beta diversity in species with high vagility was more strongly determined by spatially structured environmental variation. Altogether, both niche specialization, along the environmental gradient defined by tree architecture, and dispersal limitation are responsible for structuring arboreal spider assemblages. High dispersal capacity of spiders appears to reinforce the role of niche-related processes.


2021 ◽  
Vol 8 ◽  
Author(s):  
Mary C. Fabrizio ◽  
Troy D. Tuckey ◽  
Aaron J. Bever ◽  
Michael L. MacWilliams

The sustained production of sufficient forage is critical to advancing ecosystem-based management, yet factors that affect local abundances and habitat conditions necessary to support aggregate forage production remain largely unexplored. We quantified suitable habitat in the Chesapeake Bay and its tidal tributaries for four key forage fishes: juvenile spotted hake Urophycis regia, juvenile spot Leiostomus xanthurus, juvenile weakfish Cynoscion regalis, and bay anchovy Anchoa mitchilli. We used information from monthly fisheries surveys from 2000 to 2016 coupled with hindcasts from a spatially interpolated model of dissolved oxygen and a 3-D hydrodynamic model of the Chesapeake Bay to identify influential covariates and construct habitat suitability models for each species. Suitable habitat conditions resulted from a complex interplay between water quality and geophysical properties of the environment and varied among species. Habitat suitability indices ranging between 0 (poor) and 1 (superior) were used to estimate seasonal and annual extents of suitable habitats. Seasonal variations in suitable habitat extents in Chesapeake Bay, which were more pronounced than annual variations during 2000–2016, reflected the phenology of estuarine use by these species. Areas near shorelines served as suitable habitats in spring for juvenile spot and in summer for juvenile weakfish, indicating the importance of these shallow areas for production. Tributaries were more suitable for bay anchovy in spring than during other seasons. The relative baywide abundances of juvenile spot and bay anchovy were significantly related to the extent of suitable habitats in summer and winter, respectively, indicating that Chesapeake Bay habitats may be limiting for these species. In contrast, the relative baywide abundances of juvenile weakfish and juvenile spotted hake varied independently of the spatial extent of suitable habitats. In an ecosystem-based approach, areas that persistently provide suitable conditions for forage species such as shoreline and tributary habitats may be targeted for protection or restoration, thereby promoting sufficient production of forage for predators. Further, quantitative habitat targets or spatial thresholds may be developed for habitat-limited species using estimates of the minimum habitat area required to produce a desired abundance or biomass; such targets or thresholds may serve as spatial reference points for management.


Author(s):  
Yongyut Trisurat ◽  
Albertus G. Toxopeus

The results show that among the three approaches, the potentially suitable habitats derived from cartographic overlay cover the largest area and are likely to overestimate existing occurrence areas. The logistic regression model predicts approximately 56% as suitable area, while maximum entropy results covers approximately 9% of the sanctuary. Although the results show large differences in the suitable areas, it should not be concluded that any one method always proves better than the others. Utilization of any method is dependent on the situation and available information. If species observations are limited, the cartographic overlay or habitat suitability is recommended. The logistic regression method is recommended when adequate presence and absence data are available. If presence-only data is available, a niche-based model or the maximum entropy method (MAXENT) is highly recommended.


Author(s):  
Brian Huntley

Species’ distributions, population sizes, and community composition are affected, directly and indirectly, by climatic changes, leading to changes in location, extent, and/or quality of distributions, range fragmentation or coalescence, and temporal discontinuities in suitable conditions. Quaternary fossil records document these responses, emphasizing individualism of species’ responses and impermanence of communities. Recent observations document similar changes attributable to recent climatic changes, including rapid decreases and increases in ranges and/or populations. Both also document extinctions associated with rapid climatic changes. Modelling studies predict substantial changes in species’ distributions, population sizes, and communities in response to future climatic changes. Implicit assumptions that genetic variation enabling adaptation is ubiquitous throughout species’ ranges, or that gene flow may be sufficiently rapid to allow adaptation, may be invalid. Work is needed to investigate spatial structuring of adaptive genetic variation and rates of gene flow, and to develop new models. Without this, species extinction risks may be severely underestimated.


The Condor ◽  
2002 ◽  
Vol 104 (4) ◽  
pp. 877-881
Author(s):  
Eben H. Paxton ◽  
Mark K. Sogge ◽  
Tracy D. McCarthey ◽  
Paul Keim

AbstractUsing molecular-genetic techniques, we determined the gender of 202 Southwestern Willow Flycatcher (Empidonax traillii extimus) nestlings from 95 nests sampled over a five-year period. Overall nestling sex ratio did not vary significantly from 50:50 among years, by clutch order, or by mating strategy (monogamous vs. polygamous pairings). However, we did observe significant differences among the four sites sampled, with sex ratios biased either toward males or females at the different sites. Given the small population sizes and geographic isolation of many of the endangered subspecies' breeding populations, sex-ratio differences may have localized negative impacts.Cociente de Sexos en Polluelos de Empidonax traillii extimusResumen. Utilizando técnicas moleculares determinamos el sexo de 202 polluelos de Empidonax traillii extimus pertenecientes a 95 nidos que fueron muestreados durante un período de cinco años. En general, el cociente de sexos no varió significativamente de 50:50 entre años, ya sea por orden de la nidada o por estrategia de apareamiento (monogamia vs. poligamia). Sin embargo, observamos diferencias significativas entre los cuatro sitios muestreados, en los cuales la razón de sexos estuvo sesgada hacia los machos o las hembras dependiendo del sitio. Dados los pequeños tamaños poblacionales y el aislamiento geográfico de muchas de las poblaciones reproductivas de esta subespecie en peligro, las diferencias en el cociente de sexos pueden tener un impacto negativo a nivel local.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Bikram Shrestha ◽  
Pavel Kindlmann

AbstractThe snow leopard is one of the most endangered large mammals. Its population, already low, is declining, most likely due to the consequences of human activity, including a reduction in the size and number of suitable habitats. With climate change, habitat loss may escalate, because of an upward shift in the tree line and concomitant loss of the alpine zone, where the snow leopard lives. Migration between suitable areas, therefore, is important because a decline in abundance in these areas may result in inbreeding, fragmentation of populations, reduction in genetic variation due to habitat fragmentation, loss of connectivity, bottlenecks or genetic drift. Here we use our data collected in Nepal to determine the areas suitable for snow leopards, by using habitat suitability maps, and describe the genetic structure of the snow leopard within and between these areas. We also determine the influence of landscape features on the genetic structure of its populations and reveal corridors connecting suitable areas. We conclude that it is necessary to protect these natural corridors to maintain the possibility of snow leopards’ migration between suitable areas, which will enable gene flow between the diminishing populations and thus maintain a viable metapopulation of snow leopards.


Author(s):  
Morten Hertz ◽  
Iben Ravnborg Jensen ◽  
Laura Østergaard Jensen ◽  
Iben Vejrum Nielsen ◽  
Jacob Winde ◽  
...  

SummaryMany domestic breeds face challenges concerning genetic variability, because of their small population sizes along with a high risk of inbreeding. Therefore, it is important to obtain knowledge on their extinction risk, along with the possible benefits of certain breeding strategies. Since many domestic breeds face the same problems, results from such studies can be applied across breeds and species. Here a Population Viability Analysis (PVA) was implemented to simulate the future probability of extinction for a population of the endangered Danish Jutland cattle (Bos taurus), based on the software Vortex. A PVA evaluates the extinction risk of a population by including threats and demographic values. According to the results from the PVA the population will go extinct after 122 years with the current management. Four scenarios were created to investigate which changes in the breeding scheme would have the largest effect on the survival probabilities, including Scenario 1: More females in the breeding pool, scenario 2: More males in the breeding pool, scenario 3: Increased carrying capacity, and scenario 4: Supplementing males to the population through artificial insemination using semen from bulls used in the populations in past generations. All scenarios showed a positive effect on the population's probability of survival, and with a combination of the different scenarios, the population size seems to be stabilized.


1998 ◽  
Vol 25 (3) ◽  
pp. 262-272 ◽  
Author(s):  
M. K. PANDIT ◽  
C. R. BABU

Medicinal plants are a valuable resource for regional economic development in the tropics, and the Eastern Himalaya in particular harbours many such species. Extensive deforestation and over-exploitation in this region have brought several species to the brink of extinction, and Coptis teeta is such an endangered species; yet scientific information for its conservation is lacking. Investigations on the distribution range, demography, ecology, cytology, reproductive biology and population genetic structure of C. teeta were carried out; it was found to be endemic to a small area, to occupy a very narrow habitat and to be highly dispersed with very small population sizes. Edaphic factors were found to have played a vital role in ecological preference, natural distribution and evolutionary divergence of the species. The species exhibits a ‘K’ strategy, high male sterility, low reproductive success and efficiency, inadequate seed dispersal, and little genetic variability. A combination of these genetic hurdles and external threats in the form of habitat disturbance and over-exploitation for commercial purposes could result in its extinction. The species was found to have highly specific microsite requirements that cannot be met in other habitats. It is argued that in situ conservation measures would be the best strategy for the continued survival of this species. For effective management of the species it is recommended that its habitat be declared a protected area with the active cooperation of local inhabitants including the sharing of benefits of conservation.


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