Transient windows for connectivity in a changing world

Abstract

The primary focus of studies examining metapopulation processes in dynamic or disturbance-dependent landscapes has been related to spatiotemporal changes in the habitat patches themselves. However, like the habitat patches, opportunities for movement between patches can also exist intermittently in dynamic landscapes, creating transient connectivity windows – which we define as a period of time during which matrix conditions increase the probability of one or more individuals moving successfully between habitat patches. Far less is known about the implications of dynamic changes in connectivity per se, and, to our knowledge, there are no connectivity metrics or metapopulation models that explicitly consider intermittent changes to connectivity between habitat patches. Consequently, in this paper, we examined the peer-reviewed, published literature up to November 2013 to better understand the consequences of variability in connectivity and to highlight knowledge gaps on this topic. First, we describe how connectivity per se can vary along a temporal gradient, offering examples of ecological systems that fall along this gradient. Second, we examine how temporal variability in connectivity is important for metapopulation dynamics, particularly given likely alterations to disturbance regimes as a result of global change. We conclude our review by briefly discussing key avenues for future connectivity-related research, all of which hinge on the need to perceive connectivity as a transient feature.

Seeing It All: Evaluating Supervised Machine Learning Methods for the Classification of Diverse Otariid Behaviours

“…Foraging was predicted well, likely at the detriment of travelling. Usually, foraging behaviours are the most difficult to distinguish, particularly when they are of very short duration (such as a fish capture here or attack/peck in the plover [57]). Having a very short epoch likely allowed these behaviours to become more distinguished, while travelling behaviours became nosier.…”

Pelagic early life stages promote connectivity in the demersal labrid Choerodon rubescens

“…When a species is genetically homogeneous, it is difficult to quantify the amount of gene flow because even a small amount of gene flow is sufficient to maintain homogeneity (Waples, 1998), particularly in a species with a large effective population size (N e ) (see Hutchison and Templeton, 1999;Marko and Hart, 2011;Waples, 1998). The possible basis for the genetic homogeneity of C. rubescensranges from complete panmixia (e.g., Moore and Chaplin, 2013), through consistent but low levels of gene flow, to episodic pulses of gene flow (e.g., Zeigler and Fagan, 2014). Although it is not possible to determine which of these scenario(s) is applicable, a study of the population dynamics of C. rubescens at the southern margin of its distribution has provided evidence of interannual variation in recruitment strength in this area (Cure et al, 2015), which is consistent with the concept that gene flow is episodic.…”

Guidelines for Using Movement Science to Inform Biodiversity Policy

“…Building upon the concepts of metapopulation dynamics (Hanski 1998), reserves can be seen as reasonably stable habitat patches surrounded by less secure and potentially less suitable habitats in the matrix. If individuals can move through the matrix, even if it is providing only transient connectivity (Zeigler and Fagan 2014), then the reserve network may be able to maintain gene flow when species become locally extinct through re-colonization (Hanski 1998). However, matrix habitats are heterogeneous and tend to facilitate or impede movement in a species-specific manner (Driscoll et al 2013), and this needs to be taken into account when making management decisions.…”