Marine reserve networks for species that move within a home range

Abstract

Marine reserves are expected to benefit a wide range of species, but most models used to evaluate their effects assume that adults are sedentary, thereby potentially overestimating population persistence. Many nearshore marine organisms move within a home range as adults, and there is a need to understand the effects of this type of movement on reserve performance. We incorporated movement within a home range into a spatially explicit marine reserve model in order to assess the combined effects of adult and larval movement on persistence and yield in a general, strategic framework. We describe how the capacity of a population to persist decreased with increasing home range size in a manner that depended on whether the sedentary case was maintained by self persistence or network persistence. Self persistence declined gradually with increasing home range and larval dispersal distance, while network persistence decreased sharply to 0 above a threshold home range and was less dependent on larval dispersal distance. The maximum home range size protected by a reserve network increased with the fraction of coastline in reserves and decreasing exploitation rates outside reserves. Spillover due to movement within a home range contributed to yield moderately under certain conditions, although yield contributions were generally not as large as those from spillover due to larval dispersal. Our results indicate that, for species exhibiting home range behavior, persistence in a network of marine reserves may be more predictable than previously anticipated from models based solely on larval dispersal, in part due to better knowledge of home range sizes. Including movement within a home range can change persistence results significantly from those assuming that adults are sedentary; hence it is an important consideration in reserve design.

Home site fidelity in Black Rockfish, <em>Sebastes melanops</em>, reintroduced into a fjord environment

“…therefore, we cannot exclude the possibility that Black Rockfish spent some of their time on soft substrates immediately adjacent to the reef rather than on the reef itself. However, extensive use of the adjacent soft-bottomed habitat seems unlikely because prior studies indicate that Black Rockfish (Johnson et al 2003) and other Sebastes species (love et al 2002;o'Farrell et al 2009) select rocky habitats and use soft substrates infrequently. this does not preclude the possibility that Black Rockfish may emigrate by crossing such areas, and our study suggests that such behaviour does occur.…”

“…are vulnerable to overexploitation (love et al 2002;Berkeley et al 2004), and data on their movements and home site fidelity are important for managing the genus (Freiwald 2012). For instance, whether networks of marine reserves succeed in restoring exploited populations may depend on the extent to which dispersing juveniles and resident adults confine their movements to protected areas (Moffitt et al 2009). …”

Beyond connectivity: how empirical methods can quantify population persistence to improve marine protected‐area design

“…Their analysis showed how high levels of selfrecruitment could be commonly observed in coral reef landscapes, but did not directly address whether populations would persist at each location. Earlier models have shown how persistence in MPA networks is determined by the combination of patch size, patch spacing, and dispersal distances (Botsford et al 2001, Gerber et al 2005, Moffitt et al 2009, White et al 2010a. These earlier models did not calculate openness because that specific quantity does not arise in the analysis of persistence (Appendix A).…”

Impacts of Large Male-Selective Harvesting on Reproduction: Illustration with Large Decapod Crustacean Resources

“…The reserves are anticipated to also increase fishery yields outside the reserves through export of eggs and larvae (recruitment subsidy) and adult and juvenile export (spillover) (Gell and Roberts 2003;Goñi et al 2010). The eggs and larvae export and their effects on recruitment are anticipated to produce much greater benefits for fisheries than spillover (Moffitt et al 2009;Díaz et al 2011). Although at present uncertainty about larval connectivity and dispersal bars understanding about actual impact of reproductive output from the reserves to outside it, the dominant contribution of the reserves to the overall reproductive output of the targeted species must be remarkable and the reserves would contribute to attain a higher reproductive rate of the resources (Kaiser et al 2007;Jack and Wing 2010;Díaz et al 2011).…”