Screens and webs: Multifunctional seedling shelters contribute to Araneae restoration

Abstract

Restoring fauna is a fundamental objective of ecological restoration. For organisms that depend on vegetation structures (e.g., hunting support), such as spiders, this can be difficult, especially in early stages of intervention. Multifunctionality in restoration practices occurs when one action can achieve more than one objective. Given the complexity of restoration actions and the general scarcity in resources worldwide, this property can play a key role. Therefore, we sought to study the multifunctionality of using seedling shelters to support Araneae recolonization, through the addition of structural complexity (e.g., wire mesh structures as spider webs support). We evaluated the presence of Araneae, the percentage of shelter covered by webs and elements of structural complexity (height and number of leaves,) in 32 seedlings of four tree species that had been in the restoration process for about one year. To determine the relationship between structural complexity and Araneae abundance, we used a Generalized Additive Model (GAM). We observed spiders (95.5% Araneidae) on all monitored structures (seven on average), and an average of 5% of the shelters' area covered by webs. The variation in spider abundance in shelters was correlated to seedling height and number of leaves. The taller the seedling, the fewer spiders it had, and higher spider abundance was found when seedlings had from 25 to 30 leaves. The spatial characteristics of seedlings inside screens is a condition of the quality/availability of the shelter as a resource for spider colonization. Therefore, our results indicate a possible multifunctional property of seedling shelters in improving microhabitat structure for orb-weaver spiders, as well as preventing herbivory.