Large grazers modify effects of aboveground–belowground interactions on small-scale plant community composition

Aboveground and belowground organisms influence plant community composition by local interactions, and their scale of impact may vary from millimeters belowground to kilometers aboveground. However, it still poorly understood how large grazers that select their forage on large spatial scales interact with small-scale aboveground–belowground interactions on plant community heterogeneity. Here, we investigate how cattle (Bos taurus) modify the effects of interactions between yellow meadow ants (Lasius flavus) and European brown hares (Lepus europaeus) on the formation of small-scale heterogeneity in vegetation composition. In the absence of cattle, hares selectively foraged on ant mounds, while under combined grazing by hares and cattle, vertebrate grazing pressure was similar on and off mounds. Ant mounds that were grazed by only hares had a different plant community composition compared to their surroundings: the cover of the grazing-intolerant grass Elytrigia atherica was reduced on ant mounds, whereas the relative cover of the more grazing-tolerant and palatable grass Festuca rubra was enhanced. Combined grazing by hares and cattle, resulted in homogenization of plant community composition on and off ant mounds, with high overall cover of F. rubra. We conclude that hares can respond to local ant–soil–vegetation interactions, because they are small, selective herbivores that make their foraging decisions on a local scale. This results in small-scale plant patches on mounds of yellow meadow ants. In the presence of cattle, which are less selective aboveground herbivores, local plant community patterns triggered by small-scale aboveground–belowground interactions can disappear. Therefore, cattle modify the consequences of aboveground–belowground interactions for small-scale plant community composition

Nutritional correlates of koala persistence in a low-density population

It is widely postulated that nutritional factors drive bottom-up, resource-based patterns in herbivore ecology and distribution. There is, however, much controversy over the roles of different plant constituents and how these influence individual herbivores and herbivore populations. The density of koala (Phascolarctos cinereus) populations varies widely and many attribute population trends to variation in the nutritional quality of the eucalypt leaves of their diet, but there is little evidence to support this hypothesis. We used a nested design that involved sampling of trees at two spatial scales to investigate how leaf chemistry influences free-living koalas from a low-density population in south east New South Wales, Australia. Using koala faecal pellets as a proxy for koala visitation to trees, we found an interaction between toxins and nutrients in leaves at a small spatial scale, whereby koalas preferred trees with leaves of higher concentrations of available nitrogen but lower concentrations of sideroxylonals (secondary metabolites found exclusively in eucalypts) compared to neighbouring trees of the same species. We argue that taxonomic and phenotypic diversity is likely to be important when foraging in habitats of low nutritional quality in providing diet choice to tradeoff nutrients and toxins and minimise movement costs. Our findings suggest that immediate nutritional concerns are an important priority of folivores in low-quality habitats and imply that nutritional limitations play an important role in constraining folivore populations. We show that, with a careful experimental design, it is possible to make inferences about populations of herbivores that exist at extremely low densities and thus achieve a better understanding about how plant composition influences herbivore ecology and persistence.IW and WF received a grant from New South Wales (NSW) Department of Environment, Climate Change & Water

Multi-Scape Interventions to Match Spatial Scales of Demand and Supply of Ecosystem Services

The original focus on supply of ecosystem services is shifting toward matching supply and demand. This new focus underlines the need to consider not only the amount of ecosystem services but also their spatial and temporal distributions relative to demand. Ecosystem functions and services have characteristic or salient scales that are defined by the scales at which the producing organisms or communities exist and function. Provision of ecosystem services (ES) and functions can be managed optimally by controlling the spatio-temporal distribution of landscape and community components. A simple model represents distributions of ES as kernels centered at the location of interventions such as grassland restoration or establishment of nesting habitat for pollinators. Distribution kernels allow non-habitat patches to receive ecosystem services from species they cannot support. Simulations for three contrasting ES producing organisms (bumblebees, Northern Harriers, and oak trees) show the effects of interacting distribution of interventions and demand for ES. More ES demand is met when the intervention is spread out in the landscape and demand is evenly distributed, particularly when the kernel radius is much larger than the minimum intervention required for the ES producing unit to be established. Because different functions have different reaches and saturation points, the level of ES demand met at any point in space can be modulated by controlling the spatial distribution of landscape components created by interventions. Different ES can be promoted by the same type and quantity of intervention by controlling the continuum of scales in the distribution of interventions. This work provides a conceptual and quantitative basis to consider the spatial design of interventions to match ES supply and demand

Multi-Scape Interventions to Match Spatial Scales of Demand and Supply of Ecosystem Services

The original focus on supply of ecosystem services is shifting toward matching supply and demand. This new focus underlines the need to consider not only the amount of ecosystem services but also their spatial and temporal distributions relative to demand. Ecosystem functions and services have characteristic or salient scales that are defined by the scales at which the producing organisms or communities exist and function. Provision of ecosystem services (ES) and functions can be managed optimally by controlling the spatio-temporal distribution of landscape and community components. A simple model represents distributions of ES as kernels centered at the location of interventions such as grassland restoration or establishment of nesting habitat for pollinators. Distribution kernels allow non-habitat patches to receive ecosystem services from species they cannot support. Simulations for three contrasting ES producing organisms (bumblebees, Northern Harriers, and oak trees) show the effects of interacting distribution of interventions and demand for ES. More ES demand is met when the intervention is spread out in the landscape and demand is evenly distributed, particularly when the kernel radius is much larger than the minimum intervention required for the ES producing unit to be established. Because different functions have different reaches and saturation points, the level of ES demand met at any point in space can be modulated by controlling the spatial distribution of landscape components created by interventions. Different ES can be promoted by the same type and quantity of intervention by controlling the continuum of scales in the distribution of interventions. This work provides a conceptual and quantitative basis to consider the spatial design of interventions to match ES supply and demand

Comportamento de cordeiros em pastejo de azevém (Lolium multiflorum) em diferentes fases fenológicas submetidos à adubação nitrogenada

O objetivo deste trabalho foi avaliar o efeito de nitrogênio (N) em pastagem de azevém (Lolium multiflorum Lam.), manejada à mesma altura em pastejo contínuo, sobre o comportamento ingestivo de cordeiros de corte. Utilizaram-se o azevém com quatro doses de N, empregando-se ureia comercial (45% de N) com aplicação única, sendo: 0 kg/ha de N; 75 kg/ha de N; 150 kg/ha de N; e 225 kg/ha de N. O período de avaliação foi de 63 dias, dividido em três períodos de 21, que corresponderam aos estágios de desenvolvimento das plantas desde a fase vegetativa até o florescimento. Em cada período os dias foram divididos em três turnos de avaliação comportamental: manhã (6:30 às 10:30), meio-dia (10:31 às 14:30) e tarde (14:31 às 18:30). Na análise dos períodos, os animais diminuíram a atividade de ócio em 0,3 min a cada dia de avanço no ciclo da pastagem, independentemente do turno de avaliação. Já para o consumo de água, não houve diferença entre as fases fenológicas (média de 1,8 min por dia). Os cordeiros reduziram o tempo de ruminação em 0,612; 0,660; e 0,060 min a cada dia de utilização da pastagem nos turnos da manhã (6 : 30 - 10 : 30), meio-dia (10:31 -14:30) e tarde (14:31 - 18:30), respectivamente, ao passo que para o pastejo os tempos destinados a essa atividade aumentaram 0,726; 1,104; e 0,354 min, respectivamente. Com relação às doses de N, não houve interferência (P > 0,05) sobre as atividades de ruminação (126,6 min) e consumo de água (10,5 min). Observou-se comportamento linear crescente (P < 0,05) para ócio em 0,108 min e decrescente para pastejo em 0,198 min para cada kg de N aplicado na pastagem. O estágio fenológico do azevém influenciou as atividades comportamentais dos cordeiros