scholarly journals Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

2016 ◽  
Author(s):  
Elizabeth J Roberson ◽  
Michael J Chips ◽  
Walter P Carson ◽  
Thomas P Rooney
Keyword(s):  
Vegetation Structure ◽  
Prey Availability ◽  
Forest Disturbance ◽  
Geographic Region ◽  
Spider Webs ◽  
Spider Web ◽  
Food Web Interactions ◽  
Closed Canopy ◽  
Availability Index ◽  
Web Building

Indirect effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in Pennsylvania and Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Wisconsin sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7-12 times greater in deer-free plots. Prey availability was also higher in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread throughout the region.

scholarly journals Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

2016 ◽  
Author(s):  
Elizabeth J Roberson ◽  
Michael J Chips ◽  
Walter P Carson ◽  
Thomas P Rooney
Keyword(s):  
Vegetation Structure ◽  
Prey Availability ◽  
Forest Disturbance ◽  
Geographic Region ◽  
Spider Webs ◽  
Spider Web ◽  
Food Web Interactions ◽  
Availability Index ◽  
Web Building ◽  
Northern Highlands

Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau region Pennsylvania and Northern Highlands region of Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Northern Highlands sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7-12 times greater in deer-free plots. Prey availability was lower in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer appear to indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread.

scholarly journals Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2538 ◽  
Author(s):  
Elizabeth J. Roberson ◽  
Michael J. Chips ◽  
Walter P. Carson ◽  
Thomas P. Rooney
Keyword(s):  
Vegetation Structure ◽  
Prey Availability ◽  
Forest Disturbance ◽  
Geographic Region ◽  
Spider Webs ◽  
Spider Web ◽  
Food Web Interactions ◽  
Availability Index ◽  
Web Building ◽  
Northern Highlands

Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau region Pennsylvania and Northern Highlands region of Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Northern Highlands sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7–12 times greater in deerfree plots. Prey availability was lower in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer appear to indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread.

scholarly journals Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

2016 ◽  
Author(s):  
Elizabeth J Roberson ◽  
Michael J Chips ◽  
Walter P Carson ◽  
Thomas P Rooney
Keyword(s):  
Vegetation Structure ◽  
Prey Availability ◽  
Forest Disturbance ◽  
Geographic Region ◽  
Spider Webs ◽  
Spider Web ◽  
Food Web Interactions ◽  
Availability Index ◽  
Web Building ◽  
Northern Highlands

Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau region Pennsylvania and Northern Highlands region of Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Northern Highlands sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7-12 times greater in deer-free plots. Prey availability was lower in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer appear to indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread.

scholarly journals Interactions among Land, Water, and Vegetation in Shoreline Arthropod Communities

2004 ◽  
Vol 3 (2) ◽  
Author(s):  
Randall Willoughby ◽  
Wendy Anderson
Keyword(s):  
Vegetation Structure ◽  
Prey Availability ◽  
Vegetation Type ◽  
Missouri River ◽  
Suitable Habitat ◽  
Arthropod Communities ◽  
Web Building ◽  
Emergent Insects ◽  
Rock Lake ◽  
Land Water

We investigated the distribution and abundance of terrestrial spiders as a function of their distance from a body of water and the structure of vegetation that would provide suitable habitat. We hypothesized that spiders would prefer to be located near the water to catch abundant aquatic emergent insects. In Montana along the Upper Missouri River, and in Missouri at various locations around Table Rock Lake, transect lines were run from the water’s edge to 25 meters inland. At five-meter intervals, in one square meter plots, the number of spiders, number of prey and type, and vegetation type and structure were recorded. In both Montana and Missouri, spider distribution was more strongly associated with available vegetation structure than with distance from shore. This suggests that, although prey availability may be important for predator distribution, suitable habitat is as strong or stronger a determinant for web building spiders.

scholarly journals Dynamic environments do not appear to constrain spider web building behaviour

2021 ◽  
Vol 108 (3) ◽  
Author(s):  
Tom Mulder ◽  
Lucas Wilkins ◽  
Beth Mortimer ◽  
Fritz Vollrath
Keyword(s):  
Wind Loading ◽  
Spider Webs ◽  
Spider Web ◽  
Thread Tension ◽  
In The Wild ◽  
Orb Web ◽  
Araneus Diadematus ◽  
Orb Web Spiders ◽  
Building Behaviour ◽  
Web Building

AbstractMany laboratory experiments demonstrate how orb-web spiders change the architecture of their webs in response to prey, surroundings and wind loading. The overall shape of the web and a range of other web parameters are determined by frame and anchor threads. In the wild, unlike the lab, the anchor threads are attached to branches and leaves that are not stationary but move, which affects the thread tension field. Here we experimentally test the effect of a moving support structure on the construction behaviour and web-parameters of the garden cross spider Araneus diadematus. We found no significant differences in building behaviour between rigid and moving anchors in total time spent and total distance covered nor in the percentage of the total time spent and distance covered to build the three major web components: radials, auxiliary and capture spirals. Moreover, measured key parameters of web-geometry were equally unaffected. These results call for re-evaluation of common understanding of spider webs as thread tensions are often considered to be a major factor guiding the spider during construction and web-operation.

scholarly journals Distinct movement patterns generate stages of spider web-building

2021 ◽  
Author(s):  
Abel Corver ◽  
Nicholas Wilkerson ◽  
Jeremiah Miller ◽  
Andrew G Gordus
Keyword(s):  
Movement Patterns ◽  
Spider Webs ◽  
Spider Web ◽  
Hierarchical Hidden Markov Model ◽  
Action Sequences ◽  
Clustering Approach ◽  
Animal Architecture ◽  
Web Building ◽  
Web Construction ◽  
Physical Manifestation

The geometric complexity and stereotypy of spider webs have long generated interest in their algorithmic origin. Like other examples of animal architecture, web construction is the result of several assembly phases that are driven by distinct behavioral stages coordinated to build a successful structure. Manual observations have revealed a range of sensory cues and movement patterns used during web construction, but methods to systematically quantify the dynamics of these sensorimotor patterns are lacking. Here, we apply an analytical pipeline to quantify web-making behavior of the orb-weaver Uloborus diversus. Position tracking revealed stereotyped stages of construction that could occur in typical or atypical progressions across individuals. Using an unsupervised clustering approach, we identified general and stage-specific leg movements. A Hierarchical Hidden Markov Model revealed that stages of web-building are characterized by stereotyped sequences of actions largely shared across individuals, regardless of whether these stages progress in a typical or atypical fashion. Web stages could be predicted based on action-sequences alone, revealing that web-stages are a physical manifestation of underlying behavioral phases.

scholarly journals Effects of Forest Disturbance on Vegetation Structure and Above-Ground Carbon in Three Isolated Forest Patches of Taita Hills

2016 ◽  
Vol 06 (02) ◽  
pp. 142-161 ◽  
Author(s):  
Chemuku Wekesa ◽  
Nereoh Leley ◽  
Elias Maranga ◽  
Bernard Kirui ◽  
Gabriel Muturi ◽  
...  
Keyword(s):  
Vegetation Structure ◽  
Forest Disturbance ◽  
Forest Patches ◽  
Taita Hills

scholarly journals Distinct movement patterns generate stages of spider web building

2021 ◽  
Author(s):  
Abel Corver ◽  
Nicholas Wilkerson ◽  
Jeremiah Miller ◽  
Andrew Gordus
Keyword(s):  
Movement Patterns ◽  
Spider Web ◽  
Web Building

scholarly journals Vegetation structure and decreased moth abundance limit the recolonisation of restored habitat by the European Nightjar

2018 ◽  
Vol 3 ◽  
pp. 25-39 ◽  
Author(s):  
Nathalie Winiger ◽  
Pius Korner ◽  
Raphaël Arlettaz ◽  
Alain Jacot
Keyword(s):  
Vegetation Structure ◽  
Habitat Restoration ◽  
Stand Structure ◽  
Prey Availability ◽  
Population Declines ◽  
Major Transitions ◽  
Slowing Down ◽  
Open Forest ◽  
Mineral Soils ◽  
Management Recommendations

Woodland ecosystems of Europe have undergone major transitions in the last centuries. Changes in land use and the loss of natural forest dynamics have often led to structurally poor, uniform and dense stands. Not surprisingly, open forest species relying on a heterogeneous stand structure have suffered dramatic population declines. The European Nightjar Caprimulguseuropaeus, a nocturnal insectivorous bird, has undergone such a decline in its main Swiss stronghold in Valais. Despite the species’ potential to colonize new sites and habitat restoration measures implemented since 2001, recolonisation of restored sites has not taken place, suggesting problems with the current habitat restoration strategy. In order to refine management recommendations, we compared habitat structure and moth abundance, a key Nightjar food source, at sites that are still occupied and at sites that had been abandoned but have recently been restored. Vegetation structure was more heterogeneous and moth abundance greater at occupied than at abandoned sites. More specifically, occupied sites harboured a greater coverage of bare ground, while abandoned sites exhibited a higher amount of regeneration and intermediate shrub layer. The occurrence of natural perches was also higher in occupied sites. Abandoned sites are thus characterised by lower prey abundance and denser vegetation cover, the combination of which is likely to lead to lower prey availability for hunting Nightjars. Restoration action would benefit from maintaining snags and dead branches and by targeting unproductive habitats characterised by mineral soils, thereby slowing down regeneration and shrub regrowth. For future successful management of Nightjar habitats, it seems thereby essential trying to find the balance between actions that allow opening the lower and mid-strata of the forest while sustaining high moth populations.

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