scholarly journals Hurricane-induced population decrease in a Critically Endangered long-lived reptile

2021 ◽  
Author(s):  
Matthijs P. van den Burg ◽  
Hannah Madden ◽  
Timothy van Wagensveld ◽  
Erik Boman

Catastrophic events, like hurricanes, bring lethal conditions that can have population-altering effects. The threatened Caribbean dry forest occurs in a region known for its high-intensity hurricane seasons and high species endemism, highlighting the necessity to better understand hurricane impacts as fragmentation and clearing of natural habitat continues. However, such studies remain rare, and for reptiles are mostly restricted to Anolis. Here we used single-season occupancy modeling to infer the impact of the intense 2017 Atlantic hurricane season on the critically endangered Lesser Antillean Iguana, Iguana delicatissima. We surveyed 30 transects across eight habitats on St. Eustatius during 2017-2019, which resulted in 344 individual surveys and 98 iguana observations. Analyses of abundance and site occupancy indicated both measures for 2018 and 2019 were strongly reduced compared to the pre-hurricane 2017 state. Iguanas at higher elevations were affected more profoundly, likely due to higher wind speeds, tree damage and extensive defoliation. Overall, our results indicate a decrease in population estimates (23.3-26.5%) and abundance (22-23.8%) for 2018 and 2019, and a 75% reduction in the number of opportunistic sightings of tagged iguanas between 2017-2018. As only small and isolated I. delicatissima populations remain, our study further demonstrates their vulnerability to stochastic events. Considering the frequency and intensity of hurricanes are projected to increase, our results stress the urgent need for population-increasing conservation actions in order to secure the long-term survival of I. delicatissima throughout its range.

2015 ◽  
Author(s):  
Citlalli Morelos-Juárez ◽  
Andrea Tapia ◽  
Galo Conde ◽  
Mika Peck

Identifying key food resources for critically endangered species is vital in the design of effective conservation strategies, particularly if these resources are also targeted by anthropogenic activities such as logging. The province of Esmeraldas in NW Ecuador is heavily dependent on commercial logging. It also maintains the only healthy population of the critically endangered brown-headed spider monkey (Ateles fusciceps fusciceps). The unprotected forest remnant of Tesoro Escondido, in the buffer zone of the Cotacachi Cayapas Ecological Reserve, is home to an estimated 130 individuals of a global population of approximately 250. There is an urgent need for information to develop effective conservation action plans for the species, in particular the impact of logging activity on key feeding resources. We characterised the floristic composition of the habitat of A. f. fusciceps and estimated the availability of fruit resources for the annual cycle of 2012-2013 in sixteen 0.1 hectare vegetation plots. We determined feeding preferences for A. f. fusciceps using behavioural observations applying the Chesson ε index to identify key feeding tree species. We reviewed regional logging permits to identify species targeted for extraction by the timber industry and calculated extraction volumes in primary forest for key feeding tree species to identify potential conflict between logging and primate diet. We identified 65 fruiting tree species from 34 families that formed the diet of A. f. fusciceps. The Chesson ε index identified twelve species as preferred species with further phenological observations identifying seven species as staple foods and two palms as potential fall back fruits. Additionally, high densities of the lipid rich fruits of Brosimum utile make this an important resource for this primate throughout the year. Of 65 feeding tree species identified for A. f. fusciceps, 35 species are also targeted as sources of timber. Five key feeding species would be depleted under current sustainable management extraction protocols while two other species would be significantly impacted in terms of local abundance.Given the critically endangered status of A. f. fusciceps, remaining primary forest in NW Ecuador requires urgent protection, including thorough revision of current logging protocols to ensure long term survival of the species.


2015 ◽  
Author(s):  
Citlalli Morelos-Juárez ◽  
Andrea Tapia ◽  
Galo Conde ◽  
Mika Peck

Identifying key food resources for critically endangered species is vital in the design of effective conservation strategies, particularly if these resources are also targeted by anthropogenic activities such as logging. The province of Esmeraldas in NW Ecuador is heavily dependent on commercial logging. It also maintains the only healthy population of the critically endangered brown-headed spider monkey (Ateles fusciceps fusciceps). The unprotected forest remnant of Tesoro Escondido, in the buffer zone of the Cotacachi Cayapas Ecological Reserve, is home to an estimated 130 individuals of a global population of approximately 250. There is an urgent need for information to develop effective conservation action plans for the species, in particular the impact of logging activity on key feeding resources. We characterised the floristic composition of the habitat of A. f. fusciceps and estimated the availability of fruit resources for the annual cycle of 2012-2013 in sixteen 0.1 hectare vegetation plots. We determined feeding preferences for A. f. fusciceps using behavioural observations applying the Chesson ε index to identify key feeding tree species. We reviewed regional logging permits to identify species targeted for extraction by the timber industry and calculated extraction volumes in primary forest for key feeding tree species to identify potential conflict between logging and primate diet. We identified 65 fruiting tree species from 34 families that formed the diet of A. f. fusciceps. The Chesson ε index identified twelve species as preferred species with further phenological observations identifying seven species as staple foods and two palms as potential fall back fruits. Additionally, high densities of the lipid rich fruits of Brosimum utile make this an important resource for this primate throughout the year. Of 65 feeding tree species identified for A. f. fusciceps, 35 species are also targeted as sources of timber. Five key feeding species would be depleted under current sustainable management extraction protocols while two other species would be significantly impacted in terms of local abundance.Given the critically endangered status of A. f. fusciceps, remaining primary forest in NW Ecuador requires urgent protection, including thorough revision of current logging protocols to ensure long term survival of the species.


2019 ◽  
Vol 7 ◽  
Author(s):  
Caroline Fukushima ◽  
Jorge Mendoza ◽  
Rick West ◽  
Stuart Longhorn ◽  
Emmanuel Rivera ◽  
...  

CITES is an international agreement between governments to ensure that international trade in specimens of wild animals and plants does not threaten their survival. Regarding spiders, all species listed in CITES are tarantulas. They are included in Appendix II, meaning that they are species that are not necessarily now threatened with extinction but that they may become so unless trade is closely controlled. Many tarantulas are legally and illegally traded in the pet market and they are one of the most traded invertebrate groups. Originally, the CITES list published in 1995 included all the current species of the genus Brachypelma Simon, 1891 plus Aphonopelma pallidum (F. O. Pickard-Cambridge, 1897) and the so-called Aphonopelma albiceps (Pocock, 1903). After that, some taxonomic changes were done, as well as descriptions of new species in the genus Brachypelma. The objective of this paper is to assess the 21 taxonomically valid spider species listed on CITES according to the IUCN criteria, study the general patterns and trends and advise on possible future conservation actions critical for the survival of endangered species. Amongst all 21 species assessed, 16 had sufficient data on their distribution, ecology and threats to properly understand their current status and suggest possible conservation measures. A decline in the area of occupancy (AOO) and extent of occurrence (EOO) was inferred to almost all species, caused mostly by human activities (urbanisation, roads, agricultural and touristic activities), which often lead to the complete loss of subpopulations across their range. Hurricanes and frequent rising water, which are increasing in frequency due to climate change, can cause decline in habitat quality and consequent change in EOO and AOO of some species and should also be considered when planning conservation actions. Severe fragmentation was detected in 13 species and is therefore one of the most relevant threats to the most endangered Brachypelma species and should be made a priority aspect to deal with when proposing conservation actions for the group. Regarding the loss of individuals in wild populations, the main cause seems to be the overharvesting to meet the illegal trade. The most important conservation actions identified across species include preserving their natural habitat through protected areas, establishing management plans for both the species and their habitats and undertaking systematic monitoring to provide information about population recovery and species re-introduction programmes. In general, we propose to prioritise and support research on the population trends and distribution, as well as on the impact of land use and habitat degradation. Special attention regarding conservation actions and research plans has to be given to the central Pacific coastal area of Mexico, particularly around Guerrero State where five species of Brachypelma occur. Critically, for some of the most endangered species, such as B. baumgarteni and B. hamorii, there is no official protected area in their range of occurrence. It would therefore be highly recommended to establish at least one conservation unit which focuses on protecting each of these species in situ. In some cases, basic taxonomic research is needed before development of any appropriate conservation action can be proposed.


2022 ◽  
pp. 5-13
Author(s):  
Wayne M. Edwards

The impact of climate change on Malagasy amphibians remains poorly understood. Equally, deforestation, fragmentation, and lack of connectivity between forest patches may leave vulnerable species isolated in habitat that no longer suits their environmental or biological requirements. We assess the predicted impact of climate change by 2085 on the potential distribution of a Critically Endangered frog species, the golden mantella (Mantella aurantiaca), that is confined to a small area of the central rainforest of Madagascar. We identify potential population distributions and climatically stable areas. Results suggest a potential south-eastwardly shift away from the current range and a decrease in suitable habitat from 2110 km2 under current climate to between 112 km2 – 138 km2 by the year 2085 – less than 7 % of currently available suitable habitat. Results also indicate that the amount of golden mantella habitat falling within protected areas decreases by 86 % over the same period. We recommend research to ascertain future viability and the feasibility of expanding protection to newly identified potential sites. This information can then be used in future conservation actions such as habitat restoration, translocations, re introductions or the siting of further wildlife corridors or protected areas.


2021 ◽  
Vol 14 (1) ◽  
pp. 73-91
Author(s):  
James Rodríguez-Echeverry ◽  
Margareth Leiton

Abstract Currently, there is no precise information on the degree of transformation of Tropical Andes hotspot landscape and native ecosystems due to the intensification of agricultural and urban land-use. Proper knowledge of these changes would provide crucial information for planning conservation strategies. We evaluated the impact of the intensification of agricultural and urban land-use on the Inter-Andean Dry Forest and Tropical Montane Forest, both of which are categorized as Critically Endangered, and the state of the landscape in the High Rio Guayllabamba watershed, Ecuador, during the periods 1991–2005 and 2005–2017. The evaluation was carried out using Landsat satellite images of 30 x 30 m pixels and landscape metrics. We found an advanced state of landscape transformation. Since the 1990s, the loss of both ecosystems was largely caused by the conversion of forest to agriculture, resulting in substantial changes in the spatial configuration of these ecosystems. From 1991 to 2017, 19.8 % and 16.1 % of Inter-Andean Dry Forest and Tropical Montane Forest respectively, were converted to agriculture. The loss of Inter-Andean Dry Forest was 28 % and the number of forest patches increased by more than 150%. The loss of Tropical Montane Forest was 16.5 % and the number of forest patches increased by more than 300 %. The largest loss and fragmentation of forest cover occurred from 1991 to 2005. We suggested planning landscape-scale conservation, using the patch-corridor-matrix model. This model is appropriate given the current configuration of the landscape studied, with Inter-Andean Dry Forest and Tropical Montane Forest restricted to small patches sparsely distributed across the landscape.


Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 105
Author(s):  
Argelia E. Rascón-Ramos ◽  
Martín Martínez-Salvador ◽  
Gabriel Sosa-Pérez ◽  
Federico Villarreal-Guerrero ◽  
Alfredo Pinedo-Alvarez ◽  
...  

Understanding soil moisture behavior in semi-dry forests is essential for evaluating the impact of forest management on water availability. The objective of the study was to analyze soil moisture based in storm observations in three micro-catchments (0.19, 0.20, and 0.27 ha) with similar tree densities, and subject to different thinning intensities in a semi-dry forest in Chihuahua, Mexico. Vegetation, soil characteristics, precipitation, and volumetric water content were measured before thinning (2018), and after 0%, 40%, and 80% thinning for each micro-catchment (2019). Soil moisture was low and relatively similar among the three micro-catchments in 2018 (mean = 8.5%), and only large rainfall events (>30 mm) increased soil moisture significantly (29–52%). After thinning, soil moisture was higher and significantly different among the micro-catchments only during small rainfall events (<10 mm), while a difference was not noted during large events. The difference before–after during small rainfall events was not significant for the control (0% thinning); whereas 40% and 80% thinning increased soil moisture significantly by 40% and 53%, respectively. Knowledge of the response of soil moisture as a result of thinning and rainfall characteristics has important implications, especially for evaluating the impact of forest management on water availability.


2021 ◽  
Vol 42 (01) ◽  
pp. 051-060
Author(s):  
Vineet Agrawal ◽  
Smita Kayal ◽  
Prasanth Ganesan ◽  
Biswajit Dubashi

Abstract Background Treatment protocols for acute lymphoblastic leukemia (ALL) have evolved over time to give excellent cure rates in children and moderate outcomes in adults; however, little is known how delays in chemotherapy affect long-term survival. Objectives To find the association of delays during different treatment phases on the survival outcomes. Materials and Methods Data from 149 ALL cases treated between 2009 and 2015 were retrospectively analyzed. Treatment course in commonly used protocols was divided into three phases—induction, consolidation (postremission), maintenance, and also a combined intensive phase (induction plus consolidation) for the purpose of analysis, and delay in each phase was defined based on clinically acceptable breaks. Analysis was done to find the impact of treatment delay in each phase on the survival outcomes. Results The median age was 12 years (range, 1–57). Multi-center Protocol-841 (MCP-841) was used for 72%, German Multicenter Study Group for Adult ALL (GMALL) for 19%, and Berlin, Frankfurt, Muenster, 95 protocol (BFM-95) for 9% of patients. Delay in induction was seen in 52%, consolidation in 66%, and during maintenance in 42% of patients. The median follow-up was 41 months, and 3-year survival outcomes for the entire cohort were event-free survival (EFS)—60%, relapse-free survival (RFS)—72%, and overall survival (OS)—68%. On univariate analysis, delay in induction adversely affected EFS (hazard ratio [HR] = 1.78, p = 0.04), while delay in intensive phase had significantly worse EFS and RFS (HR = 2.41 [p = 0.03] and HR = 2.57 [p = 0.03], respectively). On separate analysis of MCP-841 cohort, delay in intensive phase affected both EFS (HR = 3.85, p = 0.02) and RFS (HR = 3.42, p = 0.04), whereas delay in consolidation significantly affected OS with (HR = 4.74, p = 0.04) independently. Conclusion Treatment delays mostly in intensive phase are associated with worse survival in ALL; attempts should be made to maintain protocol-defined treatment intensity while adequately managing toxicities.


2016 ◽  
Vol 77 (3) ◽  
pp. 542-552 ◽  
Author(s):  
J. Mertens ◽  
J. Germer ◽  
J. A. Siqueira Filho ◽  
J. Sauerborn

Abstract Spondias tuberosa Arr., a fructiferous tree endemic to the northeast Brazilian tropical dry forest called Caatinga, accounts for numerous benefits for its ecosystem as well as for the dwellers of the Caatinga. The tree serves as feed for pollinators and dispersers as well as fodder for domestic ruminants, and is a source of additional income for local smallholders and their families. Despite its vantages, it is facing several man-made and natural threats, and it is suspected that S. tuberosa could become extinct. Literature review suggests that S. tuberosa suffers a reduced regeneration leading to population decrease. At this juncture S. tuberosa cannot be considered threatened according to the International Union for Conservation of Nature Red List Categories and Criteria, as it has not yet been assessed and hampered generative regeneration is not considered in the IUCN assessment. The combination of threats, however, may have already caused an extinction debt for S. tuberosa. Due to the observed decline in tree density, a thorough assessment of the S. tuberosa population is recommended, as well as a threat assessment throughout the entire Caatinga.


Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3375
Author(s):  
Annabelle Vogt ◽  
Farsaneh Sadeghlar ◽  
Tiyasha H. Ayub ◽  
Carlo Schneider ◽  
Christian Möhring ◽  
...  

Dendritic cells (DC) as professional antigen presenting cells are able to prime T-cells against the tumor-associated antigen α-fetoprotein (AFP) for immunotherapy of hepatocellular carcinoma (HCC). However, a strong immunosuppressive tumor environment limits their efficacy in patients. The co-stimulation with CD40Ligand (CD40L) is critical in the maturation of DC and T-cell priming. In this study, the impact of intratumoral (i.t.) CD40L-expressing DC to improve vaccination with murine (m)AFP-transduced DC (Ad-mAFP-DC) was analyzed in subcutaneous (s.c.) and orthotopic murine HCC. Murine DC were adenovirally transduced with Ad-mAFP or Ad-CD40L. Hepa129-mAFP-cells were injected into the right flank or the liver of C3H-mice to induce subcutaneous (s.c.) and orthotopic HCC. For treatments, 106 Ad-mAFP-transduced DC were inoculated s.c. followed by 106 CD40L-expressing DC injected intratumorally (i.t.). S.c. inoculation with Ad-mAFP-transduced DC, as vaccine, induced a delay of tumor-growth of AFP-positive HCC compared to controls. When s.c.-inoculation of Ad-mAFP-DC was combined with i.t.-application of Ad-CD40L-DC synergistic antitumoral effects were observed and complete remissions and long-term survival in 62% of tumor-bearing animals were achieved. Analysis of the tumor environment at different time points revealed that s.c.-vaccination with Ad-mAFP-DC seems to stimulate tumor-specific effector cells, allowing an earlier recruitment of effector T-cells and a Th1 shift within the tumors. After i.t. co-stimulation with Ad-CD40L-DC, production of Th1-cytokines was strongly increased and accompanied by a robust tumor infiltration of mature DC, activated CD4+-, CD8+-T-cells as well as reduction of regulatory T-cells. Moreover, Ad-CD40L-DC induced tumor cell apoptosis. Intratumoral co-stimulation with CD40L-expressing DC significantly improves vaccination with Ad-mAFP-DC in pre-established HCC in vivo. Combined therapy caused an early and strong Th1-shift in the tumor environment as well as higher tumor apoptosis, leading to synergistic tumor regression of HCC. Thus, CD40L co-stimulation represents a promising tool for improving DC-based immunotherapy of HCC.


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