Ground-dwelling arthropods of pinyon-juniper woodlands: Arthropod community patterns are driven by climate and overall plant productivity, not host tree species

Abstract

Pinyon-juniper (PJ) woodlands have drastically changed over the last century with juniper encroaching into adjacent habitats and pinyon experiencing large-scale mortality events from drought. Changes in climate and forest composition may pose challenges for animal communities found in PJ woodlands, especially if animals specialize on tree species sensitive to drought. Here we test habitat specialization of ground-dwelling arthropod (GDA) communities underneath pinyon and juniper trees. We also investigate the role of climate and productivity gradients in structuring GDAs within PJ woodlands using two elevational gradients. We sampled 12,365 individuals comprising 115 taxa over two years. We found no evidence that GDAs differ under pinyon or juniper trees, save for a single species of beetle which preferred junipers. Climate and productivity, however, were strongly associated with GDA communities and appeared to drive differences between sites. Precipitation was strongly associated with arthropod richness, while differences in GDA composition were associated with environmental variables (precipitation, temperature, vapor pressure, and normalized difference vegetation index). These relationships varied among different arthropod taxa (e.g. ants and beetles) and community metrics (e.g. richness, abundance, and composition), with individual taxa also responding differently. Overall, our results suggest that GDAs are not dependent on tree type, but are strongly linked to primary productivity and climate, especially precipitation in PJ woodlands. This implies GDAs in PJ woodlands are more susceptible to changes in climate, especially at lower elevations where it is hot and dry, than changes in dominant vegetation. We discuss management implications and compare our findings to GDA relationships with vegetation in other systems.

Assessing the influence of elevation on satellite derived normalized difference vegetation index and land surface temperature in Rajasthan

“…Other climatic and geographic factors, like temperature, pressure, geology and rainfall are also important. This analysis is highly consistent with Uhey et al, (2020), who reported a positive correlation of NDVI with elevation.…”

Plant species composition and local habitat conditions as primary determinants of terrestrial arthropod assemblages

“…In contrast, long-term temperature data with a spatial resolution of 1 km × 1 km explained very low amounts of variation. Arthropod community composition is known to respond to long-term climate (Zellweger et al 2017 ; Uhey et al 2020 ) as well as to local-scale temperatures (Prather and Kaspari 2019 ; Uhler et al 2021 ). Plant species composition summarizes fine-scale microclimatic patterns for any desired area (here, 200-m buffer areas around the Malaise traps) and worked as a better proxy of local climatic conditions in our case.…”

“…Arthropods strongly respond to climatic conditions such as temperature, since they are ectothermic organisms (Chown and Nicolson 2004 ; Angilletta 2009 ). Several studies emphasized climate as a key driver of arthropod communities, reporting significant changes in species composition along gradients of temperature and precipitation (Lessard et al 2011 ; Uhey et al 2020 ). In addition, responses of arthropods to climate can indirectly be driven by temperature ranges of other organisms such as host plants (Hodkinson 2005 ), or microclimatic effects mediated by vegetation structure (Suggitt et al 2011 ; Prather and Kaspari 2019 ).…”

The influence of distance from crushed stone mining on surface-active arthropods and soil properties

“…Given that arthropods are known to be active mostly during the warmer months (Mavasa et al 2022) and have been reported to correlate positively with precipitation (Uhey et al 2020), we sampled in October 2021. Since the study was focused on surface-active arthropods, the pitfall trapping method was used.…”