Biology subjects

Frishkoff, L. O.

Publications and source records attributed to Frishkoff, L. O..

4 recordsLinked to original sources

bioRxiv2024

Ancient occupation by humans leads to missing bird diversity in otherwise natural habitats

Habitat modification is responsible for substantial biodiversity declines, but communities vary in their tolerance to land-use change. One infrequently queried possibility is that historical factors determine the sensitivity of contemporary communities. We use bird community data from 54 studies across the world to test the hypothesis that pre-historic human presence reduced community sensitivity to land-use change by eliminating sensitive species in natural habitats. We find that pre-historic human population size correlates with reduced sensitivity of communities. Primary vegetation in areas with larger pre-historic human populations contain fewer species today, while species richness in structurally simple agriculture is unimpacted. The greatest signal of humans impacts dates back to 12,000 YBP suggesting that early humans may have caused even more widespread extinctions, than previously appreciated. One-Sentence SummaryAreas with high human population 12,000 years ago have less biodiversity today, but are more tolerant of habitat modification

ecology↗

bioRxiv2023

Competition and the century-long decline of a once common lizard, Sceloporus consobrinus

Habitat modification and climate change are primary mechanisms responsible for historical and ongoing population declines. Species interactions however, though difficult to study, may be of similar importance. Here we use a combination of historical species records, standardized transect surveys, and staged competition trials to assess the role of competition in recent population trends and distributions of two closely related lizard species: the prairie lizard (Sceloporus consobrinus) and the Texas Spiny lizard (S. olivaceus). Occurrence data reveals divergent population trends. S. consobrinus has decreased while S. olivaceus has increased in relative frequency over the last 100 years. We analyzed spatially-aggregated records of all lizards within the range of S. consobrinus to determine the role of climate suitability, climate change, landcover, and species interactions in shaping the occurrence patterns of S. consobrinus. In contrast to other lizard species, presence of S. olivaceus was associated with substantial reductions of S. consobrinus occurrence, and explains occurrence patterns better than either climate suitability or landcover. To test whether patterns of broad scale co-occurrence are indicative of local competitive exclusion we conducted 200m transects surveys to assess lizard communities and paired this with staged behavioral trials in the lab. Despite occurring in similar habitats, and across similar regions, transect surveys revealed lower-than-expected abundance of S. consobrinus on transects containing S. olivaceus, with both species co-occurring on only 2 of 176 transects. Shifts in habitat use implicate competitive displacement, with S. consobrinus occupying areas with three times less canopy cover at sites with S. olivaceus compared to those without. Finally, behavioral trials revealed competitive dominance of S. olivaceus, which controlled the prime basking position, and initiated more interactions that led to retreat or hiding by S. consobrinus. Our study implicates competitive interactions as in important force in structuring species distributions and population trends.

ecology↗

bioRxiv2023

Morphological limitations imposed on lizards facing urbanization

Habitat conversion in general, and urbanization in particular, are thought to create ecological filters that eliminate some species while simultaneously replacing them with others that thrive under novel conditions. The specific nature of these filters is unclear, but morphology may play an important role. Here, we seek to assess which lizard morphologies are favored in urban habitats. We quantified 17 linear measurements of morphology from museum specimens from 37 lizard species from across the continental United States. We then correlate these morphological measurements with the relative incidence of observations in urban versus non-urban environments from the citizen science database iNaturalist to determine whether particular morphologies predispose species to tolerate urban environments. We then use functional diversity and morphospace volume metrics to quantify both the total amount of unique morphological diversity represented by urban associated species, versus those restricted to natural areas. Based on our results morphology appears to be filtering lizard species from urban environments. Specifically, species with intermediate body sizes and relative tails lengths, as well as larger heads and shorter hind-limbs were more likely to occupy urban zones. As a result of this filtering, there was substantially diminished morphological diversity among urban tolerant species. While natural restricted species had a high amount of morphological diversity that was unrepresented in urban tolerant species, most urban species morphologies were shared by natural restricted ones. Only a small subset of morphologies found in natural environments persist in urban ones, but urban lizards do possess a small number of unique morphological features that may facilitate their success. Strong selection pressures in evolutionarily novel environments are not only diminishing species diversity but pruning phenotypic diversity to favor a much smaller subset of functional possibilities. Due to the connection between phenotype and function, such diminished morphological diversity is likely to impact ecosystem functioning in impoverished human-modified systems.

ecology↗

bioRxiv2017

Integrating Over Uncertainty In Spatial Scale Of Response Within Multispecies Occupancy Models Yields More Accurate Assessments Of Community Composition

O_LISpecies abundance and community composition are affected not only by the local environment, but also by broader landscape and regional context. Yet determining the spatial scale at which landscapes affect species remains a persistent challenge that hinders ecologists abilities to understand how environmental gradients influence species presence and shape entire communities, especially in the face of data deficient species and imperfect species detection.\nC_LIO_LIHere we present a Bayesian framework that allows uncertainty surrounding the true spatial scale of species responses (i.e., changes in presence/absence) to be integrated directly into a community hierarchical model.\nC_LIO_LIThis scale selecting multi-species occupancy model (ssMSOM) estimates the scale of response, and shows high accuracy and correct type I error rates across a broad range of simulation conditions. In contrast, ensembles of single species GLMs frequently fail to detect the correct spatial scale of response, and are often falsely confident in favoring the incorrect spatial scale, especially as species detection probabilities deviate from perfect.\nC_LIO_LIIntegrating spatial scale selection directly into hierarchical community models provides a means of formally testing hypotheses regarding spatial scales of response, and more accurately determining the environmental drivers that shape communities.\nC_LI

ecology↗