Very high extinction risk for Welwitschia mirabilis in the northern Namib Desert

AbstractOne of the most recognisable icon of the Namib Desert is the endemic gymnosperm Welwitschia mirabilis. Recent studies indicated that climate change may seriously affect populations in the northern Namibia subrange (Kunene region) but their extinction risk has not yet been assessed. In this study, we apply IUCN criteria to define the extinction risk of welwitschia populations in northern Namibia and assign them to a red list category. We collected field data in the field to estimate relevant parameters for this assessment. We observed 1330 plants clustered in 12 small and isolated stands. The extent of occurrence has a surface of 214.2 km2 (i.e. < 5000 km2) and the area of occupancy a surface of 56.0 km2 (i.e. < 500 km2). The quality of habitat is expected to face a reduction of 69.47 % (i.e. > 50 %) as a consequence of climate change predicted in the area. These data indicate a very high extinction risk for welwitschia in northern Kunene and classify these populations as endangered (EN) according to IUCN criteria. Similar assessments for other subranges are prevented by the lack of relevant data, an issue that deserves further research attention. Our results advocate the necessity of a management plan for the species, including measures for mitigating the impact of climate change on isolated populations across its fragmented range.

Download Full-text

Endemic Juniperus Montane Species Facing Extinction Risk under Climate Change in Southwest China: Integrative Approach for Conservation Assessment and Prioritization

Biology ◽

10.3390/biology10010063 ◽

2021 ◽

Vol 10 (1) ◽

pp. 63

Author(s):

Mohammed A. Dakhil ◽

Marwa Waseem A. Halmy ◽

Walaa A. Hassan ◽

Ali El-Keblawy ◽

Kaiwen Pan ◽

...

Keyword(s):

Climate Change ◽

Potential Distribution ◽

Extinction Risk ◽

In Situ Conservation ◽

Integrative Approach ◽

Conservation Assessment ◽

Distribution Models ◽

Area Of Occupancy ◽

Annual Range ◽

The Impact

Climate change is an important driver of biodiversity loss and extinction of endemic montane species. In China, three endemic Juniperus spp. (Juniperuspingii var. pingii, J.tibetica, and J.komarovii) are threatened and subjected to the risk of extinction. This study aimed to predict the potential distribution of these three Juniperus species under climate change and dispersal scenarios, to identify critical drivers explaining their potential distributions, to assess the extinction risk by estimating the loss percentage in their area of occupancy (AOO), and to identify priority areas for their conservation in China. We used ensemble modeling to evaluate the impact of climate change and project AOO. Our results revealed that the projected AOOs followed a similar trend in the three Juniperus species, which predicted an entire loss of their suitable habitats under both climate and dispersal scenarios. Temperature annual range and isothermality were the most critical key variables explaining the potential distribution of these three Juniperus species; they contribute by 16–56.1% and 20.4–38.3%, respectively. Accounting for the use of different thresholds provides a balanced approach for species distribution models’ applications in conservation assessment when the goal is to assess potential climatic suitability in new geographical areas. Therefore, south Sichuan and north Yunnan could be considered important priority conservation areas for in situ conservation and search for unknown populations of these three Juniperus species.

Download Full-text

Very high extinction risk for Welwitschia mirabilis in the northern Namib Desert

Journal of Arid Environments ◽

10.1016/j.jaridenv.2021.104529 ◽

2021 ◽

Vol 190 ◽

pp. 104529

Author(s):

Pierluigi Bombi ◽

Daniele Salvi ◽

Titus Shuuya ◽

Leonardo Vignoli ◽

Theo Wassenaar

Keyword(s):

Extinction Risk ◽

Namib Desert ◽

Welwitschia Mirabilis ◽

Very High

Download Full-text

Arctic Plant Responses to Climate Warming: It’s Not all about Nitrogen

Inquiry@Queen's Undergraduate Research Conference Proceedings ◽

10.24908/iqurcp.9993 ◽

2018 ◽

Author(s):

Sanna Masud

Keyword(s):

Climate Change ◽

The Arctic ◽

Plant Responses ◽

Experimental Warming ◽

Nutrient Pools ◽

Research Attention ◽

Low Arctic ◽

Total Plant ◽

The Impact ◽

Deciduous Shrub

Climate change is increasing air and soil temperatures in the Arctic, likely enhancing microbial activity. Consequently, increased decomposition rates of soil organic matter and increasing nutrient supply to tundra vegetation can be expected. The impacts of experimental warming and fertilization on growth have been investigated by studying the availability of macronutrients such as N, P and C. However, other macronutrients such as S, Ca, Mg, K, and micronutrients such as Fe, Mn, Cu, and Zn have received little research attention to determine their function, biogeochemical cycling, and effect on vegetation growth in response to warming. This study investigated the impact of experimental warming responses on availability and accumulation of the latter nutrients in the principal plant species located in mesic birch hummock tundra near Daring Lake, Northwest Territories in the Canadian Low Arctic Tundra. Plants were sampled in 2011 from the replicated summer greenhouse treatment that was established in 2004. In response to warming, the principal evergreen shrub (Rhododendron) had the most enhanced growth, followed by the deciduous shrub (Birch). Since the total plant pools of these nutrients were also enhanced in the evergreen, my results strongly suggest that availability of these nutrients was not limiting growth. By contrast, the birch total plant nutrient pools were not enhanced and significant decreases in Mg, S, and K leaf concentrations were observed, suggesting that these elements may be limiting birch growth. Together, our results suggest that plant growth response to climate change in the low Arctic may depend on previously overlooked nutrient elements, and that deciduous shrub growth may be constrained relative to the evergreen response as the arctic climate warms.

Download Full-text

The distributional impact of climate change on rich and poor countries

Environment and Development Economics ◽

10.1017/s1355770x05002755 ◽

2006 ◽

Vol 11 (2) ◽

pp. 159-178 ◽

Cited By ~ 277

Author(s):

ROBERT MENDELSOHN ◽

ARIEL DINAR ◽

LARRY WILLIAMS

Keyword(s):

Climate Change ◽

Economic Sectors ◽

Poor Countries ◽

Impact Of Climate Change ◽

Market Impacts ◽

Low Latitudes ◽

Per Capita ◽

Distributional Impact ◽

The Impact ◽

Very High

This paper examines the impact of climate change on rich and poor countries across the world. We measure two indices of the relative impact of climate across countries, impact per capita, and impact per GDP. These measures sum market impacts across the climate-sensitive economic sectors of each country. Both indices reveal that climate change will have serious distributional impact across countries, grouped by income per capita. We predict that poor countries will suffer the bulk of the damages from climate change. Although adaptation, wealth, and technology may influence distributional consequences across countries, we argue that the primary reason that poor countries are so vulnerable is their location. Countries in the low latitudes start with very high temperatures. Further warming pushes these countries ever further away from optimal temperatures for climate-sensitive economic sectors.

Download Full-text

Limited potential for adaptation to climate change in a broadly distributed marine crustacean

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2011.0542 ◽

2011 ◽

Vol 279 (1727) ◽

pp. 349-356 ◽

Cited By ~ 175

Author(s):

Morgan W. Kelly ◽

Eric Sanford ◽

Richard K. Grosberg

Keyword(s):

Climate Change ◽

Local Adaptation ◽

Thermal Tolerance ◽

Extinction Risk ◽

Empirical Studies ◽

Natural Populations ◽

Adaptation To Climate Change ◽

Isolated Populations ◽

Tigriopus Californicus ◽

Standing Variation

The extent to which acclimation and genetic adaptation might buffer natural populations against climate change is largely unknown. Most models predicting biological responses to environmental change assume that species' climatic envelopes are homogeneous both in space and time. Although recent discussions have questioned this assumption, few empirical studies have characterized intraspecific patterns of genetic variation in traits directly related to environmental tolerance limits. We test the extent of such variation in the broadly distributed tidepool copepod Tigriopus californicus using laboratory rearing and selection experiments to quantify thermal tolerance and scope for adaptation in eight populations spanning more than 17° of latitude. Tigriopus californicus exhibit striking local adaptation to temperature, with less than 1 per cent of the total quantitative variance for thermal tolerance partitioned within populations. Moreover, heat-tolerant phenotypes observed in low-latitude populations cannot be achieved in high-latitude populations, either through acclimation or 10 generations of strong selection. Finally, in four populations there was no increase in thermal tolerance between generations 5 and 10 of selection, suggesting that standing variation had already been depleted. Thus, plasticity and adaptation appear to have limited capacity to buffer these isolated populations against further increases in temperature. Our results suggest that models assuming a uniform climatic envelope may greatly underestimate extinction risk in species with strong local adaptation.

Download Full-text

Ethiopian Mustard (Brassica carinata A. Braun) as an Alternative Energy Source and Sustainable Crop

Sustainability ◽

10.3390/su12187492 ◽

2020 ◽

Vol 12 (18) ◽

pp. 7492

Author(s):

Rahiel Hagos ◽

Abdulwahab Saliu Shaibu ◽

Lei Zhang ◽

Xu Cai ◽

Jianli Liang ◽

...

Keyword(s):

Climate Change ◽

Energy Source ◽

Energy Demand ◽

Alternative Energy ◽

Climate Change Impacts ◽

Oilseed Crop ◽

Research Attention ◽

Alternative Energy Source ◽

Ethiopian Mustard ◽

The Impact

Energy and food source crop demand claims to be vulnerable to climate change impacts. The new and orphan crops, which in the past have received only limited research attention but are sustainable to environmental systems, are needed. In this review, we summarize the available literature about Ethiopian mustard as an alternative energy source and its sustainable economic importance as a new promising Brassicacea crop for new opportunities in the face of producing sustainable environment and energy development. Ethiopian mustard has many advantages and can be adopted to replace crops that are susceptible to adverse environmental conditions. Ethiopian mustard is becoming a new promising Brassicaceae crop with the current global energy demand increases. However, researchers have only focused on energy source production which has resulted in developing high erucic acid varieties. This results partly in limited studies on developing Ethiopian mustard edible oil varieties. The adoption and scaling-up of this promising crop as an oilseed crop in developing countries and Mediterranean conditions can sustain the impact of climate change with the demand for food and energy debate concepts. Indeed, further agronomic, quality and genomic studies on oilseed nutritional traits for efficient breeding and utilization are needed.

Download Full-text

Colonizing Cane Toads cause population declines in native predators: reliable anecdotal information and management implications

Pacific Conservation Biology ◽

10.1071/pc970065 ◽

1997 ◽

Vol 3 (1) ◽

pp. 65 ◽

Cited By ~ 106

Author(s):

Scott Burnett

Keyword(s):

Risk Assessment ◽

Habitat Management ◽

Extinction Risk ◽

Population Declines ◽

Cane Toad ◽

Research Attention ◽

Predator Species ◽

Continental Scale ◽

Definition Of ◽

The Impact

This paper presents compelling, anecdotal evidence of severe population declines in five predator species, Dasyurus hallucatus, Varanus gouldii, V. mertensi, V. panoptes, and V. timorensis similis, in almost immediate response to Cane Toad colonization of their habitat in three widely distributed areas of northern Queensland. Furthermore, risk assessment of all quoll and monitor taxa whose distributions overlap the potential distribution of the Cane Toad in Australia (Sutherst et al. 1996), indicates that at the continental scale, three of the four quoll taxa and eight of the 20 monitor species examined are at high risk of severe population declines following Cane Toad colonization. One quoll taxon and seven monitor species are at moderate risk and five monitor species are at low risk. The definition of the threat which Cane Toads pose to native predators has received very little research attention, and fundamental questions including; which predator species are most at risk (testing of the risk assessment hypotheses presented here), the extent of these risks (is there a need to manage Cane Toad impacts upon predators?), and the contexts of intraspecific variation in relative extinction risk (for example, interactions of extinction risk with predator and Cane Toad population demography, climate, landscape, and land use), need to be assessed. Assuming that Cane Toads are found to have an impact across a range of taxa and landscapes (which I propose to be likely), management of the impact of this species on predators can be approached from two not necessarily exclusive directions; management of Cane Toad populations and management of predator populations, through both population and habitat management. At this stage, however, management from either viewpoint is constrained by a lack of published information relevant to autecology and fine scale distribution of predators.

Download Full-text

Welwitschia: Phylogeography of a living fossil, diversified within a desert refuge

Scientific Reports ◽

10.1038/s41598-021-81150-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Norbert Jürgens ◽

Imke Oncken ◽

Jens Oldeland ◽

Felicitas Gunter ◽

Barbara Rudolph

Keyword(s):

Genetic Relationships ◽

Intraspecific Diversity ◽

Gene Pools ◽

Environmental Niche ◽

Namib Desert ◽

Isolated Populations ◽

Living Fossil ◽

Rock Types ◽

Bioclimatic Variables ◽

Welwitschia Mirabilis

AbstractWelwitschia mirabilis is one of the most extraordinary plant species on earth. With a fossil record of 112 My and phylogenetically isolated within the order Gnetales, the monotypic genus Welwitschia has survived only in the northern Namib Desert in Angola and Namibia. Despite its iconic role, the biogeography, ecological niche, and evolutionary history of the species remain poorly understood. Here we present the first comprehensive map of the strongly disjunct species range, and we explore the genetic relationships among all range fragments based on six SSR markers. We also assess the variation of the environmental niche and habitat preference. Our results confirm genetic divergence, which is consistent with the hypothetical existence of two subspecies within Welwitschia. We identify an efficient geographical barrier separating two gene pools at 18.7°S in northern Namibia. We also identify further diversification within each of the two subspecies, with several different gene pools in ten isolated range fragments. Given the presence of well-isolated populations with unique gene pools and the association with different bioclimatic variables, rock types, and habitats within arid river catchments, we can hypothesize that the present intraspecific diversity may have evolved at least in part within the present refuge of the northern Namib Desert.

Download Full-text