Spider Assemblages in Costa Rican Cloud Forests: Effects of Forest Level and Forest Age

Abstract

We investigated spider assemblages in trees at three cloud forest sites and in trees isolated in pasture habitat in Monteverde, Costa Rica. Spiders were collected from two forest types (primary and secondary) within each forest site, and at two different levels (canopy and understory) within forest types and the pasture. They were identified to family or genus level and assigned to morphospecies. Araneidae and Linyphiidae were the most commonly collected families at all locations. Although spider abundance and morphospecies richness did not differ between forest types, perhaps due to their close proximity, these parameters were generally lower in the forest canopy than in the understory. Relative abundances of nearly all common spider families also differed between canopy and understory levels within forests, suggesting that distinct sub-assemblages exist. However, spider abundance and morphospecies richness did not differ between canopy and understory in pasture trees. Spiders were generally more abundant and more diverse in the pasture than the forest, possibly due to its lower elevation or its greater habitat complexity in the form of vascular epiphytes. ResumenSe investigaron las comunidades de arañas en tres sitios de bosque nuboso y en árboles de potrero en Monteverde, Costa Rica. Las arañas fueron recogidas de dos tipos de bosque (primario y secundario) en cada sitio, y a dos niveles (copa de árboles y sotobosque) en cada tipo de bosque y en árboles del potrero. Fueron identificadas al nivel de familia o genero y clasificadas como morfoespecies. Las familias Araneidae y Linyphiidae eran las más comúnes. La abundancia y cantidad de morfoespecies no variaban entre los dos tipos del bosque, tal vez porque los dos tipos de bosque estuvieron próximos. Además, la abundancia y cantidad de morfoespecias eran menos en la copa de árboles que en el sotobosque. La abundancia proporcional de casi todas las familias comúnes también era diferente entre los dos niveles, el cual puede indicar que existen comunidades distintas. No se encontraron diferencias en la abundancia y cantidad de morfoespecies entre los dos niveles de árboles en el potrero. De todas maneras, las arañas eran más abundantes y más diversas en el potrero que en el bosque, posiblemente porque el potrero tiene menos altura y tiene una estructura mas compleja en la forma de epífitas vasculares.

The goblin spiders (Araneae, Oonopidae) of the OTONGA Nature Reserve in Ecuador, with the description of seven new species

“…As stated by Dupérre and Tapia (2016), there have been few spider biodiversity studies in neotropical premontane-, low evergreen-and cloud forests (Yanoviak et al 2003, Peckmezian 2009, Maya-Morales et al 2012 and assessments of arthropod biodiversity in these systems are still rare. In addition, the comparison between studies is difficult, due to the differences in methodology and collecting techniques.…”

“…The fact that none of the other studies even mentionned the family Oonopidae in their results is an obvious bias due to the choice of their collecting technique, habitat focus and time period. Yanoviak et al (2003) and Maya-Morales et al (2012), for example, focussed their studies on spider assemblages found in trees and forest understory, while Peckmezian (2009) studied different habitats and used different techniques but only applied them for a period of six days. As such, it is not surprising that our results are quite different, and reveal for the first time that the family Oonopidae turns out to be a very important component in Neotropical forests.…”

Secondary succession has surprisingly low impact on arboreal ant communities in tropical montane rainforest

“…and in the lowlands (Floren andLinsenmair 2001, Klimes et al 2012). Studies of butterflies (Spitzer et al 1997), birds (Soh et al 2006), and spiders (Yanoviak et al 2003a) at high elevations also found variable or weak effects of succession on species richness, but strong effects on species composition and turnover among different successional stages. (Schonberg et al 2004), which found that secondary forest species were a subset of primary forest community.…”

“…For ground and litter montane ant communities, the successional trends in species diversity and composition remain equivocal as some studies documented succession having a strong effect on ant communities (Estrada andFernandez 1999, Fisher andRobertson 2002), and others a weak effect (Bustos and Ulloa-Chacon 1996). Studies of butterflies (Spitzer et al 1997), birds (Soh et al 2006), and spiders (Yanoviak et al 2003a) at high elevations also found variable or weak effects of succession on species richness, but strong effects on species composition and turnover among different successional stages.…”

Diversity and composition of arbustive spiders in an Atlantic Forest fragment and two adjacent areas

“…In Coyle's research it was utilized four different sampling techniques and he did not perform separated analyses for each sampling procedure, therefore we are not able to ascertain if arbustive spider assemblages are more sensitive to non-forested habitats in that ecosystem as it seems to be the case for the present study. It is very possible that as time passes the spider composition of intermediate stage area becomes much more similar to the composition of mature stage area since studies showed that time since formation infl uence the plant diversity of secondary forest (Tabarelli and Mantovani, 1999), which in turn would affect spider assemblage structure (Yanoviak et al, 2003;Floren and Deeleman-Reinhold, 2005). The probability of short-term colonization of a patch could be affected both by its quality and its level of connectivity (Bonte et al, 2003).…”