Ecological restoration seeks to provide quality habitat and maximize native biodiversity in small reserve areas. In restoration projects that begin on largely degraded and/or barren landscapes, constructing habitat-providing features such as hibernacula, structures for small organisms to seek refuge, can aid in the site’s colonization, particularly by small vertebrate species. In 2018, at the start of the North Campus Open Space ecological restoration project in Goleta, California, 63 hibernacula were constructed across a 90-acre landscape, scraped bare for its transformation from a golf course into coastal slough and associated habitats. These simple hibernacula consist primarily of concrete slabs (salvaged from the golf course) piled into meter-deep holes, providing many variably spaced crevices. Although these hibernacula were constructed with the intent to provide habitat for small vertebrate colonizers, a systematic assessment of their species richness and use patterns had yet to be made. Thus, in February and March of 2021, we endeavored to quantify biodiversity at the hibernacula using three survey methods: visual surveys, camera trapping, and footprint tracking tunnels. During this pilot study period, we examined 35 hibernacula for five nights each to record different species’ visitation patterns.

Visual surveys and footprint tracking tunnels were not as informative as camera trapping efforts, which revealed at least 23 vertebrate species (8 mammals/12 birds/3 reptiles) visiting the hibernacula. All 35 sites were occupied with an average of 5.28 ±1.62 species visiting each site during the 5-night camera trapping period. Ground squirrels, fence lizards, rabbits, mice, and Burrowing Owls were the most common visitors and likely occupants of these structures. Less common visitors included song and shorebird species, and meso-carnivores, two of which were new sightings at the restoration site (spotted skunk and grey fox). Occupants moved in and out of crevices and tunnels in a hibernaculum, while visitors moved over or around the structure, often investigating its entrances. Ground squirrels were the most frequently observed species and may play an ecologically important role by creating tunnels underneath the hibernacula, thereby engineering habitat for other vertebrates. Close monitoring of this process following the construction of a hibernaculum would be valuable for understanding its importance. Overall, we conclude that constructed hibernacula are a simple and low-cost method for supporting small vertebrate biodiversity and colonization at an early stage of restoration. Further implementation and monitoring of constructed habitat features are needed to determine their value, effectiveness, and contribution towards supporting biodiversity on restoration sites.

This poster was presented at the Ecological Society of America meeting, 2021.

North Campus Open Space (NCOS) is a large-scale restored habitat in the historic Devereaux slough in Goleta, California. Forty-four plywood cover boards measuring 3’ x 4’ were dispersed across NCOS in four distinct habitats (grassland, woodland, coast sage scrubland, and marshland). For over 4 years, researchers have tracked the presence of animals under these coverboards, mostly small rodents and herpetofauna, following the area’s habitat restoration. Patterns of their distribution are increasingly understood as surveys continue; however, little is known about the patterns of invertebrate distribution and the factors influencing them. Invertebrates provide essential ecosystem functions as they break down organic matter, recycling nutrients back into the ecosystem, and they can serve as insightful bioindicators of ecosystem health. Previous studies documented that in agricultural systems, mean annual precipitation and soil pH are the largest predictors of soil invertebrate richness. In this study, we test whether these variables accurately predict patterns of invertebrate richness in a restored ecosystem. We focused on two diverse macroinvertebrate taxa, Coleoptera (beetles) and Arachnida (spiders). By collecting, curating, and identifying beetles and spiders under each coverboard we were able to establish what species reside in the various habitats. We took measurements of the soil pH under each board as well as the humidity in the interspace between the soil and the board as a proxy for mean annual precipitation. Our preliminary data suggest that soil pH and relative humidity partially contribute to the distribution of macroinvertebrates within habitats. However, other factors such as cohabitation, soil type, adjacent vegetation, or other factors involved in nutrient cycling, could have larger effects on the distribution patterns of these taxa.

This poster was presented at the UCSB undergraduate research colloquium 2024.