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Habitat loss and fragmentation due to urbanization are the most pervasive threats to biodiversity in southern California. Loss of habitat and fragmentation can lower migration rates and genetic connectivity among remaining populations of native species, reducing genetic variability and increasing extinction risk. However, it may be difficult to separate the effects of recent anthropogenic fragmentation from the genetic signature of prehistoric fragmentation due to previous natural geological and climatic changes. To address these challenges, we examined the phylogenetic and population genetic structure of a flightless insect endemic to cismontane southern California, Stenopelmatus ?mahogani? (Orthoptera: Stenopelmatidae). Analyses of mitochondrial DNA sequence data suggest that diversification across southern California began during the Pleistocene, with most haplotypes currently restricted to a single population. Patterns of genetic divergence correlate with contemporary urbanization, even after correcting for (geographical information system) GIS-based reconstructions of fragmentation during the Pleistocene. Theoretical simulations confirm that contemporary patterns of genetic structure could be produced by recent urban fragmentation using biologically reasonable assumptions about model parameters. Diversity within populations was positively correlated with current fragment size, but not prehistoric fragment size, suggesting that the effects of increased drift following anthropogenic fragmentation are already being seen. Loss of genetic connectivity and diversity can hinder a population?s ability to adapt to ecological perturbations commonly associated with urbanization, such as habitat degradation, climatic changes and introduced species. Consequently, our results underscore the importance of preserving and restoring landscape connectivity for long-term persistence of low vagility native species.

The ranges of plants and animals are moving in response to recent changes in climate. As temperatures rise, ecosystems with ?nowhere to go?, such as mountains, are considered to be more threatened. However, species survival may depend as much on keeping pace with moving climates as the climate?s ultimate persistence4,5. Here we present a new index of the velocity of temperature change (km yr21), derived from spatial gradients (6C km21) and multimodel ensemble forecasts of rates of temperature increase (6Cyr21) in the twenty-first century. This index represents the instantaneous local velocity along Earth?s surface needed to maintain constant temperatures, and has a global mean of 0.42kmyr21 (A1B emission scenario). Owing to topographic effects, the velocity of temperature change is lowest inmountainous biomes such as tropical and subtropical coniferous forests (0.08 kmyr21), temperate coniferous forest, and montane grasslands. Velocities are highest in flooded grasslands (1.26kmyr21), mangroves and deserts. High velocities suggest that the climates of only 8% of global protected areas have residence times exceeding 100 years. Small protected areas exacerbate the problem in Mediterranean-type and temperate coniferous forest biomes. Large protected areas may mitigate the problem in desert biomes. These results indicate management strategies for minimizing biodiversity loss from climate change. Montane landscapes may effectively shelter many species into the next century. Elsewhere, reduced emissions, a much expanded network of protected areas, or efforts to increase species movement may be necessary.

Recording for the June 23, 2021 SDMMP Mgmt. and Mon. Coordination Meeting. Breahna Gillespie (SDSU/UC Davis) shared "Fog duration and amount impacts hydrological balance in a montane chaparral community". Kris Taniguchi-Quan (SCCWRP) shared "Evaluating Vulnerability of Streams to Hydrologic Alteration across San Diego Region"..

Prioritization of communities for monitoring was based on the following criteria: representativeness, extent, fragmentation, endangerment and threats. Aggregated communities that received high priority rankings based on several criteria include CSS and meadows & freshwater wetlands. Communities with high endangerment or threats should also receive high priority and include: Southern foredunes, Southern coastal salt marsh, Southern coastal bluff scrub, Maritime succulent scrub, Diegan coastal sage scrub, Southern maritime chaparral, Valley needlegrass grassland, Cismontane alkali marsh, Southern arroyo willow riparian forest, Southern willow scrub, Engelmann oak woodland, Torrey Pine forest, and Tecate Cypress forest. This report will: describe the current state of the MSCP Preserve, discuss natural community assemblages and alternative vegetation community classifications for the MSCP, describe the use of landscape stratification based on environmental variables as an alternative to vegetation classification, discuss the grouping of communities for the monitoring program, and prioritize natural communities for monitoring protocol development.