Corridor quality affects net movement, size of dispersers, and population growth in experimental microcosms

Abstract

Corridors are expected to increase species dispersal in fragmented habitats. However, it remains unclear how the quality of corridors influences the dispersal process, and how it interacts with corridor length and width. Here we investigate these factors using a small-scale laboratory system where we track the dispersal of the model organism Collembola Folsomia candida. Using this system, we study the effects of corridor length, width, and quality on the probability of dispersal, net movement, body size of dispersers, and the rate of change in population size after colonization. We show that corridor quality positively affected dispersal probability, net movement, and the rate of change in population size in colonised patches. Moreover, corridor quality significantly affected the size of dispersers, with only larger individuals dispersing through poor quality corridors. The length and width of corridors affected both the rate at which populations increased in colonised patches and the net number of individuals which dispersed, suggesting that these physical properties may be important in maintaining the flow of individuals in space. Our results thus suggest that corridor quality can have an important role in determining not only the probability of dispersal occurs but also the phenotypes of the individuals which disperse, with concomitant effects on the net movement of individuals and the rate of change in population size in the colonised patches.

Habitat connectivity buffers extinction under extreme droughts in experimental metapopulations

“…Both habitat patches and corridors were filled with a mixture of plaster of Paris and black dye (c. 0.5cm in thickness). Plaster of Paris acts as a substrate for the Collembola to live on which keeps moisture, whilst the black dye makes Collembola more visible for counting (Li et al 2021). To avoid moisture wicking between the different components of the landscapes (patches and corridors), plastic baffles were printed allowing the moisture of the corridors to be manipulated separately to the moisture of the patches (Fig.…”

“…We used a fully factorial experiment to investigate the interactive effects of corridor quality with drought severity and the number of drought patches across landscape on the persistence of metapopulations. In the good corridor quality treatment, corridors had 2ml of water added each week to keep them moist (Li et al 2021), whilst in the poor corridor quality treatment no water was added to the corridors. For each corridor quality treatment (i.e., good or poor), we manipulated drought in two different ways: changing the rate at which the moisture content of patches declined (i.e., drought severity), and the number of patches simultaneously experiencing drought (i.e., number of drought patches).…”

“…Corridor quality is one of the important physical properties determines corridor effectiveness and dispersal success (Bennett et al 1994, Habel et al 2020, Li et al 2021. Specifically, high quality corridors can promote dispersal, leading to greater movement rates to colonised patches compared to poor quality corridors (Li et al 2021).…”

“…Corridor quality is one of the important physical properties determines corridor effectiveness and dispersal success (Bennett et al 1994, Habel et al 2020, Li et al 2021. Specifically, high quality corridors can promote dispersal, leading to greater movement rates to colonised patches compared to poor quality corridors (Li et al 2021). Hence corridor quality may affect the stability and longevity of corridor-connected metapopulations, by facilitating or impeding movements between habitat patches.…”

Landscape configuration affects probability of apex predator presence and community structure in experimental metacommunities

“…The role dispersal plays in preventing extinction highlights why conservation practitioners may wish to promote dispersal in nature reserves. This may be achieved by adding corridors of habitat which directly connect two habitat patches (Dunning et al, 1995;Gillies et al, 2011;Haddad & Baum, 1999;Li et al, 2021), stepping stones, smaller patches of land in between two larger patches (Baum et al, 2004;Fischer & Lindenmayer, 2002), or decreasing resistance to movement in the non-habitat matrix surrounding the patches (Gascon et al, 1999). Furthermore, the quality of these connectivity elements can influence their efficacy through changes in dispersal rates and dispersal success.…”