Biology subjects

Riecke, T. V.

Publications and source records attributed to Riecke, T. V..

2 recordsLinked to original sources

bioRxiv2023

Recruitment limitation increases susceptibility to fishing-induced collapse in a spawning aggregation fishery

Aggregation-based fisheries are notorious for booms and busts driven by aggregation discovery and subsequent fishing-induced collapse. However, environment-driven sporadic recruitment in some since-protected populations has delayed recovery, suggesting recruitment-limitation may be a key driver of their population dynamics and fishery recovery potential. To glean insight into this dynamic, we focused on an overexploited temperate aggregate spawner (Barred Sand Bass; Paralabrax nebulifer) and leveraged a long-term mark-recapture data set spanning different oceanographic and harvest histories in a custom Bayesian capture-mark-reencounter modeling framework. We coupled this demographic analysis with long-term trends in sea surface temperature, harvest, adult and juvenile densities, and historical accounts in the literature. Our results point to a history of multidecadal windows of fishing opportunity and fishing-induced collapse that were largely driven by sporadic, warm water recruitment events, which may be externally sourced. Nevertheless, we found that environment-driven sporadic recruitment was not a factor impeding recovery following the last collapse, as recruitment remained elevated due to novel, anomalously warm conditions. Despite signs of incipient population recovery, spawning aggregations remain absent, indicating other potential factors (e.g., continued fishing during spawning season, residual Allee effects) have delayed fishery recovery to date. Aggregate spawner populations that are dependent on sporadic recruitment, especially those at their geographic margins, are thus highly susceptible to sudden and potentially extended periods of collapse, making them ill-suited to high CPUE fishing that occurs on spawning grounds. If the goal is to balance the protection of spawning aggregations with long-term fishery sustainability, then limiting aggregation-based fishing during spawning season may be the best insurance policy against collapse and recovery failure.

ecology↗

bioRxiv2022

Assessing risk for butterflies in the context of climate change, demographic uncertainty, and heterogenous data sources

AbstractOngoing declines in insect populations have led to substantial concern and calls for conservation action. However, even for relatively well-studied groups, like butterflies, information relevant to species-specific status and risk is scattered across field guides, the scientific literature, and agency reports. Consequently, attention and resources have been spent on a miniscule fraction of insect diversity, including a few well-studied butterflies. Here we bring together heterogenous sources of information for 396 butterfly species to provide the first regional assessment of butterflies for the 11 western US states. For 184 species, we use monitoring data to characterize historical and projected trends in population abundance. For another 212 species (for which monitoring data are not available, but other types of information can be collected), we use exposure to climate change, development, geographic range, number of host plants, and other factors to rank species for conservation concern. A phylogenetic signal is apparent, with concentrations of declining and at-risk species in the families Lycaenidae and Hesperiidae. A geographic bias exists in that many species that lack monitoring data occur in more southern states where we expect that impacts of warming and drying trends will be most severe. Legal protection is rare among the taxa with the highest risk values: of the top 100 species, one is listed as threatened under the US Endangered Species Act and one is a candidate for listing. Among the many taxa not currently protected, we highlight a short list of species in decline, including Vanessa annabella, Thorybes mexicanus, Euchloe ausonides, and Pholisora catullus. Notably, many of these species have broad geographic ranges, which perhaps highlights a new era of insect conservation in which small or fragmented ranges will not be the only red flags that attract conservation attention.

ecology↗