Search

Mammal species contribute in different ways to seed dispersal effectiveness, acting as endozoochorous dispersers, scatter-hoarders and seed predators. Seed removal by these functional mammal groups could be affected by anthropogenic drivers, such as grazing management, a common practice in drylands. We evaluated removal of seeds from a native tree species (Prosopis flexuosa) by terrestrial wildlife mammals with different functional roles, on grazed and ungrazed sites and at different times during the fruiting period of Prosopis. We offered Prosopis fruits, each containing 15 seeds, to animals and used camera traps to identify the species removing them. We obtained the number of seeds removed (1 fruit removed = 15 seeds removed) by each animal species and each functional group. Native and domestic mammals removed 65.4% of the total seeds offered; 69.5% of offered seeds were removed from the grazed area and 61% from the ungrazed site. Considering removal times, 64.25% of offered seeds were removed during the beginning of the fruiting period of Prosopis and 67% towards the end of this period. Small mammals acting either as seed predators (Graomys griseoflavus and Akodon dolores) or scatter-hoarders (Microcavia australis) were the functional mammal groups removing the highest amount of seeds. Seed predators removed more seeds from the ungrazed site, whereas the scatter-hoarder did so at the grazed site. In the ungrazed area, it would be important to ensure habitat heterogeneity in order to improve seed removal by functional groups that disperse seeds, such as endozoochorous dispersers and scatter-hoarders. [ABSTRACT FROM AUTHOR]

The ecological function of animal seed dispersal depends on species interactions and can be affected by drivers such as the management interventions applied to protected areas. This study was conducted in two protected areas in the Monte Desert: a fenced reserve with grazing exclusion and absence of large native mammals (the Man and Biosphere Ñacuñán Reserve; FR) and an unfenced reserve with low densities of large native and domestic animals (Ischigualasto Park; UFR). The study focuses on Prosopis flexuosa seed removal by different functional mammal groups: “seed predators”, “scatter-hoarders”, and “opportunistic frugivores”. Under both interventions, the relative contribution to seed removal by different functional mammal groups was assessed, as well as how these groups respond to habitat heterogeneity (i.e. vegetation structure) at different spatial scales. Camera traps were used to identify mammal species removing P. flexuosa seeds and to quantify seed removal; remote sensing data helped analyze habitat heterogeneity. In the FR, the major fruit removers were a seed predator (Graomys griseoflavus) and a scatter-hoarder (Microcavia asutralis). In the UFR, the main seed removers were the opportunistic frugivores (Lycalopex griseus and Dolichotis patagonum), who removed more seeds than the seed predator in the FR. The FR shows higher habitat homogeneity than the UFR, and functional groups respond differently to habitat heterogeneity at different spatial scales. In the FR, because large herbivores are locally extinct (e.g. Lama guanicoe) and domestic herbivores are excluded, important functions of large herbivores are missing, such as the maintenance of habitat heterogeneity, which provides habitats for medium-sized opportunistic frugivores with consequent improvement of quality and quantity of seed dispersal services. In the UFR, with low densities of large herbivores, probably one important ecosystem function this group performs is to increase habitat heterogeneity, allowing for the activity of medium-sized mammals who, behaving as opportunistic frugivores, did the most significant seed removal. [ABSTRACT FROM AUTHOR]

The biodiversity–ecosystem function literature provides a useful framework to examine many processes associated with species diversity in ecology. One such context is the maintenance of biodiversity by facilitation in arid ecosystems.Here, we examined the complex interactions between local plant species richness and the intensity of shrub facilitation for maintaining biodiversity in arid plant communities.A synthesis including a meta‐analysis was used to compile nearly 600 papers on positive interactions mediated by shrubs in dryland plant communities (search terms: shrub, positive, facilitat*) to examine whether interactions in these studies changed with reported local species richness. A total of 19 studies and 141 independent instances directly examined and reported facilitation of diversity measures in naturally assembled plant communities and provided estimates of local species richness.Synthesis. The net effect of increasing local plant species richness was negative and shifted the relative frequency of interactions with shrubs from positive to negative with increasing local species richness. This relationship suggests that increases in richness do not always enhance functions that maintain diversity in plants communities likely due to concurrent increases in the indirect negative interactions between species under shrubs or in changes in the local species pool. [ABSTRACT FROM AUTHOR]

The open source and free programming language R is a phenomenal mechanism to address a multiplicity of challenges in ecology and evolution. It is also a complex ecosystem because of the diversity of solutions available to the analyst.Packages for R enhance and specialize the capacity to explore both niche data/experiments and more common needs. However, the paradox of choice or how we select between many seemingly similar options can be overwhelming and lead to different potential outcomes.There is extensive choice in ecology and evolution between packages for both fundamental statistics and for more specialized domain‐level analyses.Here, we provide a checklist to inform these decisions based on the principles of resilience, need, and integration with scientific workflows for evidence.It is important to explore choices in any analytical coding environment—not just R—for solutions to challenges in ecology and evolution, and document this process because it advances reproducible science, promotes a deeper understand of the scientific evidence, and ensures that the outcomes are correct, representative, and robust. [ABSTRACT FROM AUTHOR]