Arthropod Predation of Vertebrates Structures Trophic Dynamics in Island Ecosystems

This study illustrates the contribution of plant and faecal microfossil records to interdisciplinary approaches on the identification, composition, taphonomy and seasonality of livestock dung materials. The focus is on the taphonomy of opal phytoliths and calcitic dung spherulites embedded within modern faecal pellets collected from pasture grounds and pens from a range of animals, including cattle, sheep and pigs from three different farms and seasons of the year in Menorca (Balearic Islands, Spain) declared a Biosphere Reserve by UNESCO. Modern reference materials provide comparative plant and dung microfossil indicators on factors affecting the formation, composition, preservation and decay of animal faeces, as well as on the diverse environmental and anthropogenic aspects influencing these. The reported results show relevant changes in phytolith and spherulite composition according to animal species and age, livestock management, seasonality, and grazing and foddering regimes. Both microfossil records provide fundamental information on taphonomic issues that are understudied, such as the variation in the digestibility among different species, including under investigated animals such as pigs, as well on the seasonality of plant and faecal microfossils that are excreted with dung as an important material for reconstructing human-environment interactions which is commonly overlooked in archaeology.

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Impact Mechanism of the Ecological Vulnerability of Highly Developed Islands Based on the Bayesian Network Model—Applied to the Changshan Islands

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18084150 ◽

2021 ◽

Vol 18 (8) ◽

pp. 4150

Author(s):

Keyu Qin ◽

Haijun Huang ◽

Jingya Liu ◽

Liwen Yan ◽

Yanxia Liu ◽

...

Keyword(s):

Bayesian Network ◽

Network Model ◽

Geographical Information ◽

Global Changes ◽

Bayesian Network Model ◽

Island Ecosystems ◽

Impact Mechanism ◽

The North ◽

Ecological Vulnerability ◽

The Impact

Islands are one of the most sensitive interfaces between global changes and land and sea dynamic effects, with high sensitivity and low stability. Therefore, under the dynamic coupling effect of human activities and frequent natural disasters, the vulnerability of the ecological environment of islands shows the characteristics of complexity and diversity. For the protection of island ecosystems, a system for the assessment of island ecosystems and studies on the mechanism of island ecological vulnerability are highly crucial. In this study, the North and South Changshan Islands of China were selected as the study area. Considering various impact factors of island ecological vulnerability, the geographical information systems (GIS) spatial analysis, field surveys, data sampling were used to evaluate island ecological vulnerability. The Bayesian network model was used to explore the impact mechanism of ecological vulnerability. The results showed that the ecological vulnerability of the North Changshan Island is higher than that of the South Changshan Island. Among all the indicators, the proportion of net primary productivity (NPP) and the steep slope has the strongest correlation with ecological vulnerability. This study can be used as references in the relevant departments to formulate management policies and promote the sustainable development of islands and their surrounding waters

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Trophic control of cryptic coralline algal diversity

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1900506116 ◽

2019 ◽

Vol 116 (30) ◽

pp. 15080-15085 ◽

Cited By ~ 9

Author(s):

Katharine R. Hind ◽

Samuel Starko ◽

Jenn M. Burt ◽

Matthew A. Lemay ◽

Anne K. Salomon ◽

...

Keyword(s):

Algal Species ◽

Trophic Dynamics ◽

Kelp Forests ◽

Negative Consequences ◽

Food Web Structure ◽

Nearshore Ecosystems ◽

Keystone Predation ◽

Ecological Patterns ◽

Ecosystem Level ◽

Algal Assemblages

Understanding how trophic dynamics drive variation in biodiversity is essential for predicting the outcomes of trophic downgrading across the world’s ecosystems. However, assessing the biodiversity of morphologically cryptic lineages can be problematic, yet may be crucial to understanding ecological patterns. Shifts in keystone predation that favor increases in herbivore abundance tend to have negative consequences for the biodiversity of primary producers. However, in nearshore ecosystems, coralline algal cover increases when herbivory is intense, suggesting that corallines may uniquely benefit from trophic downgrading. Because many coralline algal species are morphologically cryptic and their diversity has been globally underestimated, increasing the resolution at which we distinguish species could dramatically alter our conclusions about the consequences of trophic dynamics for this group. In this study, we used DNA barcoding to compare the diversity and composition of cryptic coralline algal assemblages at sites that differ in urchin biomass and keystone predation by sea otters. We show that while coralline cover is greater in urchin-dominated sites (or “barrens”), which are subject to intense grazing, coralline assemblages in these urchin barrens are significantly less diverse than in kelp forests and are dominated by only 1 or 2 species. These findings clarify how food web structure relates to coralline community composition and reconcile patterns of total coralline cover with the widely documented pattern that keystone predation promotes biodiversity. Shifts in coralline diversity and distribution associated with transitions from kelp forests to urchin barrens could have ecosystem-level effects that would be missed by ignoring cryptic species’ identities.

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