Faunal Component:

1) Mangrove rivulus, a small (<2 inches) specialized fish largely restricted to mangrove forests, is common all along the salinity gradient sampled in Shark River. Unlike most other fish, this species remains on the damp forest floor even at low tide when the forests drain. Its abundance in the forests independent of salinity regime, suggests it is unlikely to be affected by salinity changes associated with global change. Its abundance along Shark River also has implications for the considered listing of this species under the Endangered Species Act: it is presently a species of special concern. Our work demonstrates that the species is not rare, but is rather a habitat specialist not captured in traditional fishery surveys. It thrives wherever mangrove forests are relatively intact.

Figure 1F. Mangrove rivulus are common in mangrove forests along Shark River, and are distributed, seemingly independent of site salinity. [larger image]

Relevance to resource managers: Mangrove rivulus are not a good indicator species for salinity changes associated with global change. Consideration for listing under the Endangered Species Act should take into account the species' abundance along Shark River in Everglades National Park.

This study supports the second bullet under "Milestones, Products, and Payoffs" of Question 8.2 of the "Strategic Plan for the Climate Change Science Program Final Report, July 2003". (See section starting with "Reports describing the potential consequences of global....")

Figure 2F. Frillfin gobies are common in mangrove forests along Shark River, and their distribution is closely correlated with site salinity. [larger image]

2) The distribution of Frillfin goby (Bathygobius soporator), the most abundant fish captured in tidal mangrove forests along Shark River, is closely and positively correlated with average salinity along the sampled gradient. Frillfin gobies are apparently primarily a marine species. Coupled with their abundance in tidal forests, they could serve as a good indicator species for salinity changes associated with rising sea level.

Relevance to resource managers: Frillfin gobies may be a good indicator species for salinity changes associated with global change or other factors.

This study supports the second bullet under "Milestones, Products, and Payoffs" of Question 8.2 of the "Strategic Plan for the Climate Change Science Program Final Report, July 2003". (See section starting with "Reports describing the potential consequences of global....")

3) The species composition of fish samples taken from intertidal rivulets draining forests and mudflats in the Big Sable Creek complex differs substantially. Briefly, although many common estuarine species occur in both habitats, mudflat samples are overwhelmingly dominated by water-column schooling fishes (herrings, anchovies), species rare or absent in forest samples. Cluster analysis, a statistical technique that groups objects based on their similarity, consistently groups mudflat and forest samples into different clusters, a reflection of their different species composition.

4) Mudflat sites have generated more than twice the number of species than have forested ones. From the perspective of the entire complex of six interconnected creeks, it is clear that the combination of forests and mudflats results in an increase in fish diversity at this locale.

Figure 3F. Simplified plot from cluster analysis of fish samples collected from replicate mudflats (brown shading) and forests (green shading) in the Big Sable Creek complex. Based on estimates of similarity of species composition, fish samples from forests and mudflats are distinct from each other. [larger image]

Studies 3 and 4:

Relevance to resource managers: Resource managers can judge whether documented differences in fish communities from mangrove forests versus mudflats warrants intervention to promote forest regeneration.

This study supports the second bullet under "Milestones, Products, and Payoffs" of Question 8.2 of the "Strategic Plan for the Climate Change Science Program Final Report, July 2003". (See section starting with "Reports describing the potential consequences of global....")

5) The dead wood so abundant in headwater creeks in the Big Sable Creek complex provides important habitat for federally listed diamondback terrapins. These large logs apparently resulted from the category 4-5 hurricanes of 1935 and 1960. They likely serve two roles for terrapins: refuge from predators, and a place to forage. Diamondback terrapins are estuarine turtles that occur in salt marsh and mangrove habitats. Their populations are threatened in many locales from habitat loss, nest predation, and mortality from bycatch in the blue crab fishery.

Figure 4F. Log jams in headwater creeks of the Big Sable Creek complex appear to be favored habitat for diamondback terrapins in this system. [larger image]

Relevance to resource managers: Resource managers can use this information on habitat association to target these or similar areas for long-term monitoring of an endangered species.

This study supports the second bullet under "Milestones, Products, and Payoffs" of Question 8.2 of the "Strategic Plan for the Climate Change Science Program Final Report, July 2003". (See section starting with "Reports describing the potential consequences of global....")