Diversity and seasonal variation of ground and understory spiders from a tropical mountain cloud forest

Abstract

We made intensive samplings to study the seasonal response of spiders across different forest strata (ground and understory) in a tropical mountain cloud forest from Mexico. We sampled spiders from ten plots in six sampling events during the dry and rainy season, to analyze their abundance, structure (distribution of abundance among species), diversity and the response of the five dominant species at each stratum. Results demonstrated that seasonal patterns of spider communities differed among strata, revealing a complex spatiotemporal dynamic. Abundance, structure, diversity of ground spiders, as well as the responses of four dominant species at this stratum, showed low seasonal variations. In contrast, a strong seasonal variation was observed for the understory assemblage, with lowest abundance and highest diversity in the rainy season, and different assemblage structures for each season. Seasonal patterns of each assemblage seem linked to the responses of their dominant species. We found high co-occurrence among most of the ground dominant species with similar habitat use and with multivoltine patterns, contrasting with low co-occurrence among most of the understory dominant species with similar habitat use and univoltine patterns. Our results showed that the spiders' assemblages of tropical mountain cloud forest (opposed to what is found in temperate and boreal forests) increase their species richness with the height, and that their responses to seasonal change differ between strata. Management programs of these habitats should consider the spatial and temporal variations found here, as a better understanding of their ecological dynamics is required to support their sustainable management.

Dietary preferences and feeding strategies of Colombian highland woolly monkeys

“…This suggests that woolly monkeys must have digestive strategies like chitinase enzymes or longer retention times that could facilitate the microbial fermentation and break down of chitin 94 , 95 . From our results, it is evident how much time the monkeys from this population invest in foraging for arthropods, which can be mainly attributed to a large number of epiphytic substrates in the canopy that can harbour a great number of arthropods 30 , 91 .…”

“…Although geometric moths were overall one of the most abundant arthropods in the study, which might be explained by the hypothesis that Andean rainforests elevations might act as biodiversity hotspots of animals such as insects, birds and vascular plants 89 , 90 , it is evident in the metabarcoding sequences that woolly monkeys forage for geometric moths even when other arthropods are more abundant and available in the canopy. Indeed, Andean cloud forests have a high diversity of moths and spiders, as well as a great number of newly discovered species in these unexplored regions 89 , 91 , 92 . We believe woolly monkeys are most likely able to find moths all over the canopy despite variables such as canopy strata, insect biological rhythms (e.g.…”

“…moss and bromeliads), that in Andean and sub-Andean forests harbour a high number of insects, arachnids and terrestrial crustaceans 16 , 30 . These tropical rainforests possess high humidity, allowing the relatively constant occurrence of arthropods over time 91 , 96 . Despite finding no differences in the number of arthropods that could be found among substrates, 72% of the arthropod foraging events were registered in moss, being by far the substrate the monkeys invested most time in foraging, in comparison with bromeliads, leaves or flowers.…”

The effect of seabird presence and seasonality on ground‐active spider communities across temperate islands

“…In Panama, web‐building spider activity‐density was lower in the dry season, when conditions likely reduced the availability of their prey, compared to the wet season (Lubin, 1978 ). In Mexican tropical mountain cloud forests, strong seasonal variability in understory dwelling spider abundance, community structure, and diversity were detected; however, little seasonal variability was detected in ground spiders (Campuzano et al, 2020 ). In temperate forests of Greece, seasonal differences were found in ground spider species richness, but not in abundance (Zografou et al, 2017 ).…”

Season determines the efficiency of a rapid sampling protocol for non‐acarine arachnids (Chelicerata: Arachnida) in Afrotemperate grassland biotopes

“…Seasonality is an important factor to consider when identifying optimal periods for sampling spiders (Cardoso et al 2007), as the seasonal fluctuations in temperature and rainfall patterns have major effects on spider phenology, assemblage composition and species richness (e.g. Mineo et al 2010;Campuzano et al 2020).…”