Regional Invasive Species & Climate Change Management Challenge: Forest Pest Risk is Heating Up

Insect pests and pathogens, and climate change, each threaten forest health. But what happens when the two are combined? Climate change brings pests to new areas, makes pests more damaging, reduces trees’ defenses to pests, and can alter how forests recover after pest disturbance. Strategies for managing the combined impacts of forest pests and climate change include preventing new pest introductions, resisting pest spread by treating individual trees and diversifying forest stands, promoting more resilient forests that can rebound from pests, and helping forests transition to a state better adapted to our future climate

Species richness and composition differ in response to landscape and biogeography

ContextUnderstanding how landscape patterns affect species diversity is of great importance in the fields of biogeography, landscape ecology and conservation planning, but despite the rapid advance in biodiversity analysis, investigations of spatial effects on biodiversity are still largely focused on species richness.ObjectivesWe wanted to know if and how species richness and species composition are differentially driven by the spatial measures dominating studies in landscape ecology and biogeography. As both measures require the same limited presence/absence information, it is important to choose an appropriate diversity measure, as differing results could have important consequences for interpreting ecological processes.MethodsWe recorded plant occurrences on 112 islands in the Baltic archipelago. Species richness and composition were calculated for each island, and the explanatory power of island area and habitat heterogeneity, distance to mainland and structural connectivity at three different landscape sizes were examined.ResultsA total of 354 different plant species were recorded. The influence of landscape variables differed depending on which diversity measure was used. Island area and structural connectivity determined plant species richness, while species composition revealed a more complex pattern, being influenced by island area, habitat heterogeneity and structural connectivity.ConclusionsAlthough both measures require the same basic input data, species composition can reveal more about the ecological processes affecting plant communities in fragmented landscapes than species richness alone. Therefore, we recommend that species community composition should be used as an additional standard measure of diversity for biogeography, landscape ecology and conservation planning

Regional Invasive Species & Climate Change Management Challenge: Nuisance Neonatives. Guidelines for Assessing Range-Shifting Species

Native species will need to shift their ranges northward and upslope to keep pace with climate change in the Northeast U.S. However, this may cause some range-shifting species to have undesirable consequences in their expanded range. We provide a framework to identify the likelihood that a range-shifting species will become problematic and offer suggestions to minimize impacts from these species in the recipient habitat

ECOLOGY AND PHYTOCHEMISTRY OF THE NON-NATIVE PLANT THLASPI ARVENSE (BRASSICACEAE) IN SUBALPINE MEADOWS OF COLORADO, USA

Climate change is altering ecosystems at multiple scales. Globally, warming temperatures and increasing irregularity of precipitation will have large scale impacts on species distribution and success. Locally, understanding species response to fine scale microhabitat variation can provide key insights into population adaptation. Non-native plants represent an opportunity to investigate population level response and adaptation to relatively novel combinations of biotic and abiotic environments. Subalpine meadows are at the intersection of biotic and abiotic change, as large-scale climatic shifts alter water and temperature regimes and species range shifts become increasingly common and larger in scale. This dissertation addresses these questions of biological change and local adaptation through field and greenhouse studies on the plant Thlaspi arvense (Brassicaceae) in the Rocky Mountains of Colorado, USA. Thlaspi arvense is a non-native mustard plant that is becoming more prevalent in subalpine meadows, where biological invasions have been relatively. In the subalpine ecosystems of the Rocky Mountains, climate change is predicted to fluctuate precipitation, alter snowmelt timing, vi and increase disturbance regimes. These factors can exert selection pressure to adapt to new conditions, and/or lead to a shift in the spatial distribution of plant species and communities. T. arvense produces secondary chemicals called glucosinolates, which can alter soil microbial composition, impede the growth of neighboring plants, and deter herbivory. The continued expansion of T. arvense into the Rocky Mountains poses a threat to native subalpine ecosystems but is also an opportunity to study the interface between microevolution and ecology of this species as it spreads across a changing landscape. We surveyed ten subalpine meadow sites over a three year span and conducted common garden experiments with two populations of T. arvense to investigate population adaptation and divergence of morphology and phytochemical production. We found evidence of directional selection at early snowmelt sites in the field, morphological differences between populations in a common garden, and significant increase of glucosinolate production in response to water limitation in the greenhouse. These results indicate that T. arvense is adapting to microsite variation in subalpine meadows and may retain the ability to upregulate glucosinolate production in response to stress across population

Revisiting 27 islands in the Stockholm archipelago after a century – the effect of land use change on species composition

Land use change and effects of functional and spatial connectivity on historical and present biodiversity pattern

Spatial scale and specialization affect how biogeography and functional traits predict long-term patterns of community turnover

1. Immigration, extirpation and persistence of individual populations of species are key processes determining community responses to environmental change. However, they are difficult to study over long time periods without corresponding historical and modern-day species occurrences. 2. We used historical and present-day plant species occurrence data from two different spatial scales (resolutions) to investigate the plant community turnover during the 20th century in a Baltic Sea archipelago. Patterns of turnover were analysed in relation to plant functional traits relating to dispersal and competition/persistence, as well as biogeographical variables. 3. Turnover was largely driven by interactions between functional traits and measures of area, connectivity and distance to mainland. However, the combinations of traits and biogeographical variables that were most important for predicting immigration and extirpation differed between data sets, and between species associated with grassland management and the entire species pool. 4. Taller plants were more likely to persist regardless of scale and biogeography, reflecting the grazing abandonment that occurred in the study area. Interactions between dispersal traits and biogeography were related to immigrations when the entire species pool was considered. However, increased dispersal potential, a smaller island size and increasing distance to mainland combined to promote extirpations in management-associated species. A perennial life span and seed banking contributed to species persistence. At the larger spatial scale, trait-driven turnover was not mediated by the biogeographical context. 5. We showed that it is important to consider functional traits, biogeographical variables and their interactions when analysing community turnover over time. Furthermore, we found that the understanding of how combinations of traits and biogeography predict turnover depends on the source and spatial scale of the available data, and the species pool analysed