Quantifying trade-offs between sampling effort and biodiversity detection to optimize cave monitoring design

Fišer, Cene (author), Di Batista Borko, Špela (author), Benko, Grega (author), Bračko, Gregor (author), Delić, Teo (author), Kos, Anja (author), Premate, Ester (author), Pekolj, Anja (author), Rexhepi, Behare (author), Zakšek, Valerija (author), Zagmajster, Maja (author)

Reliable biodiversity indicators require sampling designs that balance detection performance and feasibility. Subterranean ecosystems are particularly challenging due to inaccessibility and spatial complexity, and quantitative guidance on sampling strategy is limited. We quantified trade-offs between sampling effort and biodiversity detection to optimize cave monitoring design. Using three caves that provide access to the same geologically connected subterranean system in central Slovenia, we established a reference inventory of obligate subterranean species (troglobionts) through year-round spatially and temporally replicated sampling. We then evaluated 2511 alternative sub-sampling schemes derived from the full design to assess how reduced effort affects detection performance. A total of 118 taxa were recorded, including 21 troglobionts. Rarefaction analyses indicate that the regional troglobiont pool was fully captured by the complete sampling design. Sub-sampling analyses show that only a limited number of scheme combinations reliably detected ≥90% of reference troglobiont species. However, high detection performance can be maintained with substantially reduced effort when spatial replication, seasonal coverage, and complementary sampling methods are retained. By explicitly linking sampling effort to detection proportion relative to a reference baseline, this study provides a quantitative framework for evaluating and optimizing biodiversity monitoring designs. The approach is applicable to other spatially fragmented or difficult-to-survey ecosystems where efficient indicator performance is required under logistical constraints.

• Language: English
• Keywords: biological monitoring, caves, Natura 2000, sampling, troglobionts
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 9 str.
• Numbering: Vol. 191, article no. ǂ115562
• PID: 20.500.12556/RUL-189399
• UDC: 591.5
• ISSN on article: 1872-7034
• DOI: 10.1016/j.ecolind.2026.115562
• COBISS.SI-ID: 293379587
• Publication date in RUL: 05.10.2026

Record is a part of a journal

• Title: Ecological indicators
• Publisher: Elsevier Ltd.
• ISSN: 1872-7034
• COBISS.SI-ID: 84424195

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: biološki monitoring, jame, Natura 2000, vzorčenje, troglobionti