In the Shadow of Cormorants: Succession of Avian Colony Affects Selected Groups of Ground Dwelling Predatory Arthropods

Ondřej Machač,Povilas Ivinskis,Ivan Hadrián Tuf,Ondřej Horňák,Jolanta Rimšaitė

doi:10.3390/f13020330

Ondřej Machač, Povilas Ivinskis + Show 3 more

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https://doi.org/10.3390/f13020330

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Journal: Forests	Publication Date: Feb 17, 2022
Citations: 3	License type: CC BY 4.0

Affiliation: Palacký University, Olomouc, Nature Research Centre

Abstract

(1) Nesting of the great cormorants strongly influences terrestrial ecosystems by physical destruction of vegetation and chemical changes in the soil and around the nesting colonies. (2) We investigated spider, harvestmen, and centipede assemblages in different influenced plots (starting colony, active dense colony, and partly abandoned colony) in the biggest Lithuanian cormorant colony in pine woods on the shore of the Baltic Sea in the Curonian Spit National Park in Lithuania. Selected groups of ground dwelling predatory arthropods were collected by pitfall traps in 2012–2014. (3) We recorded a total of 4299 spider specimens (102 species), 451 harvestmen specimens (9 species), and 1537 centipede specimens (7 species). The coverage of moss and herb vegetation, mean Ellenberg value for light, bare ground without vegetation, and number of nests significantly influenced the abundance, species richness, and ecological groups of arthropod predators. (4) Active ground hunters represented by spider Trochosa terricola and centipede Lithobius forficatus were positively influenced by bare ground without vegetation and a higher density of nests, and negatively influenced by an increasing coverage of moss and herbs. The opposite effect was found for web builder spiders and less movable species, represented by dominant spider species Diplostyla concolor and harvestmen Nemastoma lugubre and Oligolophus tridens. (5) The results show how cormorant influence the forest vegetation structure and affect the abundance and species diversity of ground dwelling predatory arthropods.

Highlights

The great cormorant (Phalacrocorax carbo L.) is a common avian fish predator with global distribution, especially in the Northern Hemisphere [1]
(4) Active ground hunters represented by spider Trochosa terricola and centipede Lithobius forficatus were positively influenced by bare ground without vegetation and a higher density of nests, and negatively influenced by an increasing coverage of moss and herbs
In comparison with the control plot (D), the presence of a cormorant colony had a negative effect to opiliones

Summary

Introduction

The great cormorant (Phalacrocorax carbo L.) is a common avian fish predator with global distribution, especially in the Northern Hemisphere [1]. Populations of great cormorants have recently been rising all over Europe [2,3]. Cormorants roost and breed in numerous colonies in peaceful localities close to lakes and river areas or on the sea coast [4]. Cormorant nests are usually on the tops of trees; up to 50 nests may be on one tree [2]. Nesting colonies are often reused for several years, but sometimes nesting trees are changed after one season [2,5]. Among the entire population of all species of coastal birds, cormorants demonstrate the greatest impact on their coastal terrestrial ecosystems [5]

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