Directly labelling locus-specific primers for microsatellite analysis is expensive and a common limitation to small-budget molecular ecology projects. More cost-effective end-labelling of PCR products can be achieved through a three primer PCR approach, involving a fluorescently labelled universal primer in combination with modified locus-specific primers with 5' universal primer sequence tails. This technique has been widely used but has been limited largely due to a lack of available universal primers suitable for co-amplifying large numbers of size overlapping loci and without requiring locus-specific PCR conditions to be modified. In this study, we report a suite of four high-performance universal primers that can be employed in a three primer PCR approach for efficient and cost-effective fluorescent end-labelling of PCR fragments. Amplification efficiency is maximized owing to high universal primer Tm values (approximately 60+ °C) that enhance primer versatility and enable higher annealing temperatures to be employed compared with commonly used universal primers such as M13. We demonstrate that these universal primers can be combined with multiple fluorophores to co-amplify multiple loci efficiently via multiplex PCR. This method provides a level of multiplexing and PCR efficiency similar to microsatellite fluorescent detection assays using directly labelled primers while dramatically reducing project costs. Primer performance is tested using several alternative PCR strategies that involve both single and multiple fluorophores in single and multiplex PCR across a wide range of taxa.

Understanding the relationship between disturbance regimes and species diversity has been of central interest to ecologists for decades. For example, the intermediate disturbance hypothesis proposes that diversity will be highest at intermediate levels of disturbance. Although peaked (hump-shaped) diversity-disturbance relationships (DDRs) have been documented in nature, many other DDRs have been reported as well. Here, we begin to theoretically unify these diverse empirical findings by showing how a single simple model can generate several different DDRs, depending on the aspect of disturbance that is considered. Additionally, we elucidate the competition-mediated mechanism underlying our results. Our findings have the potential to reconcile apparently conflicting empirical results on the effects of disturbance on diversity.disturbance aspects | coexistence mechanisms | relative nonlinearity | plant competition T he effects of disturbance on species diversity have been studied for decades (1-5), but no clear consensus has been reached. Understanding how different disturbance regimes affect competitive outcomes is important, because disturbance regimes in many locations are changing rapidly, and these changes can have potentially profound effects on ecosystems (6-8). Moreover, human control of disturbances such as mowing, burning, grazing, and flooding can be a useful tool for conservation and management efforts (9). The lack of a clear predictive understanding of the effects of disturbance has even led some to question whether disturbance actually plays a strong role in structuring communities (10). We provide here a conceptual framework that helps to reconcile many of the diverse perspectives and research findings on disturbance and diversity.Many different patterns of variation in community diversity across disturbance gradients have been observed in nature. The effects of disturbance on species diversity can be described graphically with diversity-disturbance relationships (DDRs), which plot a measure of species diversity (e.g., richness) against a dependent variable that is a quantity related to disturbance (e.g., intensity). Mackey and Currie (10) conducted a metaanalysis of empirical disturbance studies and found that increasing, decreasing, and U-shaped DDRs can all be found in nature. Moreover, they found no trend among the studies for any specific shape to be more common than the others. This finding is ostensibly in contrast to the pattern predicted by the well-known intermediate disturbance hypothesis (IDH), which suggests a tendency for peaked, unimodal DDRs to be the most common.Connell influentially summarized the IDH by the claim that "diversity is higher when disturbances are intermediate on the scales of frequency and intensity" (2), though similar ideas had been presented previously (e.g., in refs. 1, 11, and 12). Indeed, if predation is included in the definition of disturbance (3), then the work of Paine (13) can be seen as an important early step in understanding how disturbance can affect ...

Forest regeneration following disturbance is a key ecological process, influencing forest structure and function, species assemblages, and ecosystem-climate interactions. Climate change may alter forest recovery dynamics or even prevent recovery, triggering feedbacks to the climate system, altering regional biodiversity, and affecting the ecosystem services provided by forests. Multiple lines of evidence -including global-scale patterns in forest recovery dynamics; forest responses to experimental manipulation of CO 2 , temperature, and precipitation; forest responses to the climate change that has already occurred; ecological theory; and ecosystem and earth system models -all indicate that the dynamics of forest recovery are sensitive to climate. However, synthetic understanding of how atmospheric CO 2 and climate shape trajectories of forest recovery is lacking. Here, we review these separate lines of evidence, which together demonstrate that the dynamics of forest recovery are being impacted by increasing atmospheric CO 2 and changing climate. Rates of forest recovery generally increase with CO 2 , temperature, and water availability. Drought reduces growth and live biomass in forests of all ages, having a particularly strong effect on seedling recruitment and survival. Responses of individual trees and whole-forest ecosystems to CO 2 and climate manipulations often vary by age, implying that forests of different ages will respond differently to climate change. Furthermore, species within a community typically exhibit differential responses to CO 2 and climate, and altered community dynamics can have important consequences for ecosystem function. Age-and species-dependent responses provide a mechanism by which climate change may push some forests past critical thresholds such that they fail to recover to their previous state following disturbance. Altered dynamics of forest recovery will result in positive and negative feedbacks to climate change. Future research on this topic and corresponding improvements to earth system models will be a key to understanding the future of forests and their feedbacks to the climate system.

Many native animal and plant species have highly fragmented distributions as a result of widespread habitat destruction and the ongoing onslaught of invasive species (Frankham et al., 2019). As a result, remnant populations are often small and isolated, rendering them vulnerable to the negative effects of genetic drift and inbreeding (Frankham, 2015; Weeks et al., 2011; Willi et al., 2013). These processes can lead to the expression of deleterious alleles (known as genetic load, see Willi et al., 2013) and reductions in overall population fitness (known as inbreeding depression, see Frankham, 1995), and elevate risks of maladaptation by compromising locally adapted