scholarly journals Impact of Predator Exclusion and Habitat on Seroprevalence of New World Orthohantavirus Harbored by Two Sympatric Rodents within the Interior Atlantic Forest

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1963
Author(s):  
Briana Spruill-Harrell ◽  
Anna Pérez-Umphrey ◽  
Leonardo Valdivieso-Torres ◽  
Xueyuan Cao ◽  
Robert D. Owen ◽  
...  
Keyword(s):  
Atlantic Forest ◽  
Biodiversity Loss ◽  
Forest Degradation ◽  
Landscape Composition ◽  
Exclusion Experiment ◽  
Mammalian Predators ◽  
Species Abundances ◽  
Sampling Session ◽  
Predator Exclusion ◽  
The Face

Understanding how perturbations to trophic interactions influence virus–host dynamics is essential in the face of ongoing biodiversity loss and the continued emergence of RNA viruses and their associated zoonoses. Herein, we investigated the role of predator exclusion on rodent communities and the seroprevalence of hantaviruses within the Reserva Natural del Bosque Mbaracayú (RNBM), which is a protected area of the Interior Atlantic Forest (IAF). In the IAF, two sympatric rodent reservoirs, Akodon montensis and Oligoryzomys nigripes, harbor Jaborá and Juquitiba hantavirus (JABV, JUQV), respectively. In this study, we employed two complementary methods for predator exclusion: comprehensive fencing and trapping/removal. The goal of exclusion was to preclude the influence of predation on small mammals on the sampling grids and thereby potentially reduce rodent mortality. Following baseline sampling on three grid pairs with different habitats, we closed the grids and began predator removal. By sampling three habitat types, we controlled for habitat-specific effects, which is important for hantavirus–reservoir dynamics in neotropical ecosystems. Our six-month predator exclusion experiment revealed that the exclusion of terrestrial mammalian predators had little influence on the rodent community or the population dynamics of A. montensis and O. nigripes. Instead, fluctuations in species diversity and species abundances were influenced by sampling session and forest degradation. These results suggest that seasonality and landscape composition play dominant roles in the prevalence of hantaviruses in rodent reservoirs in the IAF ecosystem.

Assessing the role of generalist predators in the biological control of alfalfa weevil (Coleoptera: Curculionidae)

2017 ◽  
Vol 149 (4) ◽  
pp. 525-533 ◽  
Author(s):  
Tatyana A. Rand
Keyword(s):  
United States ◽  
Biological Control ◽  
Experimental Work ◽  
United States Of America ◽  
Acyrthosiphon Pisum ◽  
The United States ◽  
Generalist Predators ◽  
Alfalfa Weevil ◽  
Exclusion Experiment ◽  
Predator Exclusion

AbstractAlfalfa weevil (Coleoptera:Curculionidae) is a major pest of alfalfa throughout the United States of America. Biological control research has disproportionately focussed on introduced parasitoids. Generalist predators may also be important, but experimental work evaluating their impacts is lacking. I combined a cross-site survey with a predator exclusion experiment to identify key predators, and test for impacts on weevil survival and plant defoliation levels in Montana and North Dakota, United States of America. Spiders (Araneae) dominated the complex, followed by Nabidae (Hemiptera) and Coccinellidae (Coleoptera). None of the dominant predators showed aggregative responses to weevil (Hypera postica (Gyllenhal); Coleoptera: Curculionidae) or pea aphid (Acyrthosiphon pisum (Harris); Hemiptera: Aphididae) densities across 10 sites surveyed. However, weevil densities were positively correlated with both coccinellid and nabid densities across transects at the experimental site. Thus, predator groups traditionally associated with aphids can show strong aggregative numerical responses to alfalfa weevil larvae at smaller scales. Predator exclusion revealed no significant predator effects on larval survival or alfalfa damage. However, final densities of pea aphids were significantly higher in exclusion treatments relative to controls. The results suggest that even under conditions where predators exert significant pressure on aphids, they may still have minimal impacts on weevils. Additional experimental work is necessary to determine the broader potential of generalist predators as alfalfa weevil control agents.

scholarly journals Anthropogenic impacts on Late Holocene land-cover change and floristic biodiversity loss in tropical southeastern Asia

2021 ◽  
Vol 118 (40) ◽  
pp. e2022210118 ◽  
Author(s):  
Zhuo Zheng ◽  
Ting Ma ◽  
Patrick Roberts ◽  
Zhen Li ◽  
Yuanfu Yue ◽  
...  
Keyword(s):  
Late Holocene ◽  
Southern China ◽  
Anthropogenic Impacts ◽  
Biodiversity Loss ◽  
Freshwater Wetland ◽  
Social Changes ◽  
Rice Agriculture ◽  
Human Land Use ◽  
Key Species ◽  
The Face

Southern China and Southeast Asia witnessed some of their most significant economic and social changes relevant to human land use during the Late Holocene, including the intensification and spread of rice agriculture. Despite rice growth being associated with a number of earth systems impacts, how these changes transformed tropical vegetation in this region of immense endemic biodiversity remains poorly understood. Here, we compile a pollen dataset incorporating ∼150,000 identifications and 233 pollen taxa to examine past changes in floral biodiversity, together with a compilation of records of forest decline across the region using 14 pollen records spanning lowland to mountain sites. Our results demonstrate that the rise of intensive rice agriculture from approximately 2,000 y ago led not only to extensive deforestation but also to remarkable changes of vegetation composition and a reduction in arboreal diversity. Focusing specifically on the Tertiary relic tree species, the freshwater wetland conifer Glyptostrobus (Glyptostrobus pensilis), we demonstrate how key species that had survived changing environmental conditions across millions of years shrank in the face of paddy rice farming and human disturbance.

scholarly journals Food sovereignty: an alternative paradigm for poverty reduction and biodiversity conservation in Latin America

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 235 ◽  
Author(s):  
M Jahi Chappell ◽  
Hannah Wittman ◽  
Christopher M Bacon ◽  
Bruce G Ferguson ◽  
Luis García Barrios ◽  
...  
Keyword(s):  
Latin America ◽  
Biodiversity Conservation ◽  
Land Reform ◽  
Market Integration ◽  
Poverty Reduction ◽  
Food Sovereignty ◽  
Rural Poverty ◽  
Rural Livelihoods ◽  
Biodiversity Loss ◽  
The Face

Strong feedback between global biodiversity loss and persistent, extreme rural poverty are major challenges in the face of concurrent food, energy, and environmental crises. This paper examines the role of industrial agricultural intensification and market integration as exogenous socio-ecological drivers of biodiversity loss and poverty traps in Latin America. We then analyze the potential of a food sovereignty framework, based on protecting the viability of a diverse agroecological matrix while supporting rural livelihoods and global food production. We review several successful examples of this approach, including ecological land reform in Brazil, agroforestry,milpa, and the uses of wild varieties in smallholder systems in Mexico and Central America. We highlight emergent research directions that will be necessary to assess the potential of the food sovereignty model to promote both biodiversity conservation and poverty reduction.

scholarly journals Factors affecting germination and establishment success of an endemic cactus of the Chihuahuan Desert

2020 ◽  
Author(s):  
Eder Ortiz-Martínez ◽  
Jordan Golubov ◽  
María C. Mandujano ◽  
Gabriel Arroyo-Cosultchi
Keyword(s):  
Seed Germination ◽  
Seed Bank ◽  
Developmental Stages ◽  
Seedling Recruitment ◽  
Chihuahuan Desert ◽  
Exclusion Experiment ◽  
Factors Affecting ◽  
Nurse Plants ◽  
Predator Exclusion ◽  
Storage Times

AbstractSeed and seedling are the most critical stages of cacti life cycle. From the thousands of seeds produced in a reproductive season, only a small fraction gets to germinate, the rest gets lost due to predation or gets potentially buried in the seed bank. These early stages depend on facilitation by nurse plants for germination and seedling recruitment. In this paper, we aim to describe some aspects of the recruitment of Cephalocereus polylophus. We tested the viability of seeds with different storage times as an indicator of their potential to form a short-term seed bank. Through the analysis of seed germination and seedlings survival under the canopy of two nurse plant species and open areas, we aimed to assess the importance of facilitation for recruitment. A predator exclusion experiment was used to evaluate the intensity of herbivory on seeds and seedlings of different developmental stages. Seeds had germination rates above 90%, even after two years of storage. Seed germination was only registered under one of the two nurses. After two years, up to 19% of the seedlings planted under both nurse plants survived. Protection against herbivores increased survival chances from 30 to 52 % for all age-group seedlings. Considering that facilitation is a crucial interaction for C. polylophus, future conservation programs should include the protection of plant communities.

scholarly journals Role of Forest Resources to Local Livelihoods: The Case of East Mau Forest Ecosystem, Kenya

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
D. K. Langat ◽  
E. K. Maranga ◽  
A. A. Aboud ◽  
J. K. Cheboiwo
Keyword(s):  
Construction Material ◽  
Forest Products ◽  
Biodiversity Loss ◽  
Forest Degradation ◽  
Forest Resources ◽  
Fuel Wood ◽  
Local Livelihoods ◽  
Forest Income ◽  
Forest Use

Forests in Kenya are threatened by unsustainable uses and conversion to alternative land uses. In spite of the consequences of forest degradation and biodiversity loss and reliance of communities on forests livelihoods, there is little empirical data on the role of forest resources in livelihoods of the local communities. Socioeconomic, demographic, and forest use data were obtained by interviewing 367 households. Forest product market survey was undertaken to determine prices of various forest products for valuation of forest use. Forest income was significant to households contributing 33% of total household income. Fuel wood contributed 50%, food (27%), construction material (18%), and fodder, and thatching material 5% to household forest income. Absolute forest income and relative forest income (%) were not significantly different across study locations and between ethnic groups. However, absolute forest income and relative forest income (%) were significantly different among wealth classes. Poor households were more dependent on forests resources. However, in absolute terms, the rich households derived higher forest income. These results provide valuable information on the role of forest resources to livelihoods and could be applied in developing forest conservation policies for enhanced ecosystem services and livelihoods.

scholarly journals Effect of exposure to carbofuran on the behavior and metabolism of the Atlantic Forest lambari Deuterodon iguape (Eigenmann 1907), a native species from Brazil

2021 ◽  
Author(s):  
Ricardo Claudionor Mendes ◽  
MARCELO Barbosa HENRIQUES ◽  
Edison Barbieri
Keyword(s):  
Oxygen Consumption ◽  
Atlantic Forest ◽  
Swimming Speed ◽  
Native Species ◽  
Ammonia Excretion ◽  
Biodiversity Loss ◽  
Aquatic Biodiversity ◽  
Dorsal Fin ◽  
Behavioral Parameters ◽  
The Subject

Abstract One of the major causes of aquatic biodiversity loss is the contamination of the environment by pesticides. Although there is a considerable amount of studies on the subject, there are still few that deal with the effects of carbofuran on native species in Brazil. Although carbofuran is widely used in Brazil, its action on native organisms, such as the Atlantic Forest lambari Deuterodon iguape , has not yet been studied. This work aimed to evaluate the effects of exposure to carbofuran on the fish D. iguape , considering the behavior and specific oxygen consumption and specific ammonia excretion as end points. Opercular movements, dorsal fin movements and swimming speed were analyzed as behavioral parameters. To assess specific oxygen consumption and specific ammonia excretion, fish were subjected to concentrations of 0.0, 0.05, 0.1, 0.25, and 0.5 mg/L, for 24 hours. For behavior analysis, fish remained exposed to carbofuran at concentrations: 0.0, 0.01, 0.05, 0.1 and 0.5 mg/L, in periods of 0, 2, 24 and 48 hours. The behavior was studied through filming, analyzed with the free software, Tracker 4.92 (Open Source Physics). The results showed that there was a decrease in opercular movements (-8%±2.65), in dorsal fin movements (-18.6%±2.97), as well as in swimming speed (-66.4%±1.83). There was an increase in oxygen consumption of 58.4% and ammonia excretion by 90.6% in fish exposed to the highest concentration of carbofuran. Thus, it is concluded that carbofuran altered D. iguape 's behavior, oxygen consumption and ammonia excretion. The species was sensitive to carbofuran concentrations and can be used as a bioindicator.

Desertification and Development: some broader contexts

2020 ◽  
Author(s):  
Mike Kirkby
Keyword(s):  
Water Resources ◽  
Agricultural Land ◽  
Global Climate ◽  
Urban Expansion ◽  
Biodiversity Loss ◽  
Human Action ◽  
Soil Sealing ◽  
Irrigation Potential ◽  
The Face ◽  
Physical Effects

<p>The dominant direct physical processes responsible for desertification are water erosion, wind erosion and salinization.  Other threats that degrade the soil  include loss of biodiversity, loss of soil organic matter, fire, changing water resources, soil compaction, soil sealing and contamination. Soil management inevitably combines  human and physical effects.  Climate, which is the most important driver of the physical systems, is now being rapidly modified by human action, and at a scale which is much coarser than any local remedial action. </p><p>  </p><p>In a model of near-subsistence systems, productivity is limited by climate and available labour, with some options for additional inputs through improved seed, fertilizer or tillage equipment. Optimum solutions in a particular environment depend on both climate and access to markets.  Agricultural surpluses, if any, allow investment in infrastructure – some of it directly  supporting agriculture through irrigation and market systems, some less directly useful through, for example, warfare or pyramid building.</p><p> </p><p>Today some traditional drivers of desertification may no longer be relevant, as land, particularly in the global South, is grabbed for intensive irrigated farming, and populations move into mega-cities. The dominant drivers may become soil sealing around cities and transfers of urban and irrigation water.  In semi-arid areas this will lead to competition for the best land – for urban expansion and agricultural land with irrigation potential.  Desertification then becomes an issue increasingly focussed on abandoned marginal land, maintaining biodiversity, managing regional water resources and controlling erosion in the face of global climate change.</p>

scholarly journals Early post-settlement mortality of the scallop Pecten fumatus and the role of algal mats as a refuge from predation

2015 ◽  
Vol 72 (8) ◽  
pp. 2322-2331 ◽  
Author(s):  
T. Mendo ◽  
J. M. Lyle ◽  
N. A. Moltschaniwskyj ◽  
J. M. Semmens
Keyword(s):  
Benthic Invertebrates ◽  
Algal Biomass ◽  
Adult Population ◽  
Field Observations ◽  
Exclusion Experiment ◽  
Abundance Patterns ◽  
Predator Exclusion ◽  
Settlement Substrate ◽  
Marine Benthic Invertebrates

Abstract Early post-settlement mortality is one of the main processes determining distribution and abundance patterns of marine benthic invertebrates. Most scallops have an attached phase as spat before they release the byssus and move onto the soft sediments. Thus, spat differ from other stages of life in their use of microhabitat, lack of mobility, and therefore in their vulnerability to mortality processes such as predation. However, the contribution of predation to explain levels of mortality experienced by spat and early juvenile scallops is unknown. Complex habitats such as seagrasses and algae provide a substrate upon which spat can attach and might confer an advantage as a refuge from predation. This study investigates the contribution of early post-settlement predation on abundance of Pecten fumatus and determines the role of the algae Hincksia sordida as a refuge from predation. Data were collected using field observations, a predator exclusion experiment, and tethering techniques. Mortality of up to 85% during the first weeks after settlement appeared to have prevented the establishment of an adult population at our study site. Mats of the macroalgae H. sordida provided a settlement substrate for P. fumatus spat. However, increased algal biomass did not provide greater protection from predation to juvenile scallops than lower algal biomass. Our study suggests that prey survival in submersed vegetation is likely to be dynamic among years, and affected by prey behaviour and density as well as the characteristics of the submerged vegetation.

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