Treesearch

When alien plant species arrive in a new environment, they develop novel interactions with native biota that can range from negative to positive. Determining the nature and strength of these interactions is integral to understanding why some aliens are suppressed and others become highly invasive pests. For introduced terrestrial plants, seed and seedling interactions with native biota are crucial, because most nascent populations start from seed. Herein, we explored interactions between native generalist rodent and bird consumers and seeds of the invasive wild cucumber Echinocystis lobata...

Millennia of extensive grazing, agriculture, and timber harvesting have altered Turkey’s native vegetation and modified fire regimes. The degree to which this is so is a topic for debate among policy-makers, managers, and scientists - with implications for understanding the potential impacts of land use and climate change on future forest management. While rapid urbanization, modern agribusiness, intensive forest management, and fire suppression continue to dominate the Turkish landscape, the dynamics of land use and climate change raise questions about the sustainability of future...

In 2017, we found 17 dead females of Megachile frigida Smith in clear plastic bags of composted bark mulch in a residential yard in Bozeman, Montana, USA. Females apparently entered bags via small ventilation holes, then became trapped and died. To investigate whether this is a common source of mortality, we deployed unmodified bags of mulch and those fitted with cardboard tubes (as potential nest sites) at three nearby sites in 2018. We found two dead M. frigida females and five completed leaf cells in one of these bags of mulch fitted with cardboard tubes; two male M. frigida emerged...

Exotic plant species commonly exploit disturbances more successfully than native plants. This outcome is widely attributed to the fact that disturbance reduces biotic resistance from native plant competitors. However, biocrusts, communities of mosses, lichens, and micro‐organisms, are a prominent component of semi‐arid grasslands occurring in the interstitial spaces between vascular plants. Biocrusts may provide an important source of biotic resistance to invaders, different from native plant competition, but poorly understood.

Understanding controls on recruitment is critical to predicting community assembly, diversity, and coexistence. Theory posits that at mean fecundity, recruitment of highly fecund small-seeded plants should be primarily microsite limited, which is indicated by a saturating recruitment function. In contrast, species that produce fewer large seeds are more likely to be seed-limited, which is characterized by a linear recruitment function. If these patterns hold in nature, seed predation that disproportionately affects larger-seeded species can limit their establishment. We tested these...

Climate and land-use change are predicted to lead to widespread changes in population dynamics, but quantitative predictions on the relative effects of these stressors have not yet been examined empirically. We analyzed historical abundance data of 110 terrestrial bird species sampled from 1983 to 2010 along 406 Breeding Bird Survey (BBS) across the western USA. Using boosted-regression trees, we modeled bird abundance at the beginning of this interval as a function of (1) climate variables, (2) Landsat-derived landcover data, (3) the additive and interactive effects of climate and...

Tree mortality is of considerable concern, but the magnitude and extent of forest canopy decline are relatively unknown in landscapes with high levels of topographic complexity, spatial heterogeneity, and species diversity. We assessed 30 years of canopy decline, including a 5-year period characterized by extreme drought, in one of North America’s most diverse landscapes in the Klamath Mountains of northern California, USA.

The relative importance of habitat fragmentation versus loss on species richness has been much debated. However, recent findings that fragmentation effects are relatively weak may be an artifact of using human-classified vegetation rather than adopting a species-eye view to measure landscape structure.

Climate and land‐use changes are expected to be the primary drivers of future global biodiversity loss. Although theory suggests that these factors impact species synergistically, past studies have either focused on only one in isolation or have substituted space for time, which often results in confounding between drivers. Tests of synergistic effects require congruent time series on animal populations, climate change and land‐use change replicated across landscapes that span the gradient of correlations between the drivers of change. Using a unique time series of high‐resolution climate...

Wildland fire scientists and land managers working in fire-prone areas require spatial estimates of wildfire potential. To fulfill this need, a simulation-modelling approach was developed whereby multiple individual wildfires are modelled in an iterative fashion across a landscape to obtain location-based measures of fire likelihood and fire behaviour (e.g. fire intensity, biomass consumption). This method, termed burn probability (BP) modelling, takes advantage of fire spread algorithms created for operational uses and the proliferation of available data representing wildfire patterns,...