Peeling the Layers of Caddisfly Diversity on a Longitudinal Gradient in Karst Freshwater Habitats Reveals Community Dynamics and Stability

Abstract

Freshwater biodiversity is facing a severe crisis due to many human impacts, yet the diversity dynamics of freshwater communities and possibilities of assessing these are vastly unexplored. We aimed at emphasizing different aspects of portraying diversity of a species-rich, aquatic insect group (caddisflies; Trichoptera) across four different habitats in an anthropogenically unimpacted, connected karst barrage lake/riverine system. To define diversity, we used common indices with pre-set sensitivity to species abundance/dominance; i.e., sensitivity parameter (species richness, Shannon, Simpson, Berger-Parker) and diversity profiles based on continuous gradients of this sensitivity parameter: the naïve and non-naïve diversity profiles developed by Leinster and Cobbold. The non-naïve diversity profiles show diversity profiles with regard to the similarity among species in terms of ecological traits and preferences, whereas the naïve diversity profile is called mathematically “naïve” as it assumes absolute dissimilarity between species that is almost never true. The commonly used indices and the naïve diversity profile both ranked the springs as least diverse and tufa barriers as most diverse. The non-naïve diversity profiles based on similarity matrices (using feeding behavior and stream zonation preferences of species), showed even greater differences between these habitats, while ranking stream habitats close together, regardless of their longitudinal position. We constructed the Climate Score index (CSI) in order to assess how diversity and species’ vulnerability project the community’s resistance and/or resilience to climate change. The CSI ranked the springs as most vulnerable, followed by all habitats longitudinally placed below them. We highlight the importance of integrating ecological information into biodiversity and vulnerability assessment of freshwater communities.

The Emergence of the Family Scirtidae (Insecta: Coleoptera) in Lotic Karst Habitats: A Case Study over 15 Years

“…Water temperature proved to be the most important environmental factor for the emergence of the family Scirtidae in the studied area. This is already known for many other aquatic insects groups inhabiting Plitvice Lakes NP [32,33,35,36,40,[72][73][74]. The water temperature influences the individual growth rate, metabolism and thus the timing of emergence of aquatic insects [75][76][77].…”

Karst Springs: Isolated Ecosystem Ecology from the Water Mite Perspective

“…13.3) and is most likely linked to insect emergence patterns. The emergence apex of most freshwater insects in springs in the Dinaric Karst has been recorded in the summer [36,37]. This means that in the spring, prior to their emergence, mites thrive and proliferate in their surroundings where a vast array of both prey (for deutonymph and adult individuals) and hosts (for larvae) are available.…”

Defining Patterns and Rates of Natural vs. Drought Driven Aquatic Community Variability Indicates the Ongoing Need for Long Term Ecological Research

“…The present study aims to overcome interruptions by other stressors and the continuous-comprehensive research issues that arise when trying to determine the effects of climate change. This was conducted by using 13-year biological and ecological data on insect emergence patterns to examine the effects of climate change on an otherwise unimpacted freshwater ecosystem kept under a strict conservation regime for over seven decades, the perennial barrage lake system of the Plitvice Lakes National Park in Croatia [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ].…”