Benefits to poorly studied taxa of conservation of bird and mammal diversity on islands

Abstract

Protected area delineation and conservation action are urgently needed on marine islands, but the potential biodiversity benefits of these activities can be difficult to assess due to lack of species diversity information for lesser known taxa. We used linear mixed effects modeling and simple spatial analyses to investigate whether conservation activities based on the diversity of well-known insular taxa (birds and mammals) are likely to also capture the diversity of lesser known taxa (reptiles, amphibians, vascular land plants, ants, land snails, butterflies, and tenebrionid beetles). We assembled total, threatened, and endemic diversity data for both well-known and lesser known taxa and combined these with physical island biogeography characteristics for 1190 islands from 109 archipelagos. Among physical island biogeography factors, island area was the best indicator of diversity of both well-known and little-known taxa. Among taxonomic factors, total mammal species richness was the best indicator of total diversity of lesser known taxa, and the combination of threatened mammal and threatened bird diversity was the best indicator of lesser known endemic richness. The results of other intertaxon diversity comparisons were highly variable, however. Based on our results, we suggest that protecting islands above a certain minimum threshold area may be the most efficient use of conservation resources. For example, using our island database, if the threshold were set at 10 km(2) and the smallest 10% of islands greater than this threshold were protected, 119 islands would be protected. The islands would range in size from 10 to 29 km(2) and would include 268 lesser known species endemic to a single island, along with 11 bird and mammal species endemic to a single island. Our results suggest that for islands of equivalent size, prioritization based on total or threatened bird and mammal diversity may also capture opportunities to protect lesser known species endemic to islands.

Applying global criteria to tracking data to define important areas for marine conservation

“…We use seabirds to demonstrate our approaches because they must return to land to breed, and are therefore much easier to study than other wide‐ranging marine taxa. Moreover, seabirds are top predators that utilize resources across broad oceanic regions making them good indicator species, (Caro & O'Doherty, ; Branton & Richardson, ) and information on their distributions can therefore provide surrogates for biodiversity hotspots in marine spatial planning (Zacharias & Roff, ; Aslan et al ., ). Processing and analysis of tracking data is complex, and previous efforts have typically developed species‐ and study‐specific methods (Burger & Shaffer, ).…”

Seabird population changes following mammal eradications on islands

“…In addition, the fact that seabirds often have a well-defined and largely synchronous breeding season, particularly on higher latitude islands, means only a single, suitably timed visit is required each year. Finally, conspicuous vertebrates, like seabirds, can represent umbrella species whose improved status, achieved via island restoration, promotes benefits to other lesser known taxa (Aslan et al, 2015).…”

Improving effectiveness of systematic conservation planning with density data

“…Our approach thus made the greatest use of available data while controlling for variable survey quality to correct for imperfect detection and other sources of sampling error. We illustrated the utility of our approach with terrestrial breeding birds, which are good indicators of ecosystem quality and conservation need (Blair ; Aslan et al ). However, we recommend researchers test our approach with other taxa and investigate whether the approach can be refined.…”