Over the past two years (2024 and 2025), eDNA results have been encouraging and informative. <\/p>\n
In 2024, approximately 326 species were detected across the sites; this rose to 527 in 2025.<\/p>\n
\u201cThese exciting results showcase rich biodiversity, including 233 insect species, 93 plants, 15 fish, 23 birds, 11 mammals, plus crustaceans, molluscs, spiders, amphibians, and microorganisms,\u201d Murphy said.<\/p>\n
Two rare and declining freshwater mussel species (k\u0101kahi) Echyridella menziesii and the much rarer Echyridella aucklandica have been detected. <\/p>\n
E. menziesii were consistently detected at several sample locations in both years, while E. aucklandica were detected at one site in both years.<\/p>\n
\u201cTheir presence signals areas of ecological value worth prioritising for protection and restoration,\u201d Whatley said.<\/p>\n
\u201cWhat\u2019s more, being filter feeders, protecting this population can contribute to increasing the overall health of our river. <\/p>\n
\u201cK\u0101kahi have a complex life cycle which requires a healthy native freshwater fish community to complete.<\/p>\n
\u201cThey are also sensitive to pests such as koi carp, catfish and rats and pollutants like sediment, excessive nutrients and pesticides. <\/p>\n
\u201cWhile eDNA testing allows us to detect the presence of these species, we don\u2019t know anything about the population and whether they are reproducing.\u201d<\/p>\n
Detection of mammals increased from eight species in 2024 to 11 in 2025. <\/p>\n
Common detections included rat (ship and Norway), possum, cattle, sheep, dog and mouse, with others such as cat, rabbit and stoat at single sample locations.<\/p>\n
Mangatangi Maramarua Catchment Group chairman Will Murphy.<\/p>\n
\u201cPatterns varied by year and location, with more possum and cattle DNA in 2025, possibly influenced by the hot, dry autumn drawing animals to water. This provided valuable insights into pest and land-use pressures.\u201d<\/p>\n
Twenty-six bird species were detected, including 11 natives such as p\u016bkeko, sacred kingfisher, kerer\u016b, t\u016b\u012b, fantail and silvereye.<\/p>\n
Widespread detections of sacred kingfisher, silvereye, song thrush and mallard highlight a strong avian presence, with particularly high diversity at certain sample locations (up to 15 species at one site).<\/p>\n
A very rare freshwater mussel species (k\u0101kahi) E. aucklandica (top); and a declining freshwater mussel species E. menziesii (bottom) have been detected in the Mangatangi and Maramarua catchment. Photo \/ Earth Sciences NZ \u2013 Michele Melchior<\/p>\n
Rare fish species<\/p>\n
Sixteen fish species were detected, with 10 natives, including threatened longfin eel, lamprey, \u012bnanga, giant k\u014dkopu and potentially, shortjaw k\u014dkopu.<\/p>\n
\u201cThese are all declining nationally due to habitat loss and water-quality issues. <\/p>\n
\u201cShortfin and longfin eels and Cran\u2019s bully were found at all sample sites. <\/p>\n
\u201cIntroduced and pest species such as koi carp, goldfish, gambusia, catfish and rudd appeared at several locations, but were notably absent at two headwater sites.\u201d<\/p>\n
Giant k\u014dkopu were detected at three locations in the catchment. Photo \/ Rod Morris<\/p>\n
Biological indicators derived from eDNA of macroinvertebrates (MCI), Fish IBI (index of biotic integrity), and TICI (taxon independent community index), reveal some environmental impacts overall, but with brighter spots.<\/p>\n
\u201cThe headwater and upper catchment sample locations showed the least impact, reflecting milder pollution and habitat impacts, supporting greater native biodiversity, compared to the downstream sites.<\/p>\n
\u201cLower-scoring sites suggested nutrient\/sediment stress in places, yet still supported diverse fish and important k\u0101kahi populations, which underscores restoration potential.\u201d<\/p>\n
This eDNA work, alongside broader monitoring, empowers the community to make informed decisions, track changes and better targeting of actions such as pest control and habitat enhancement.<\/p>\n
The Mangatangi Maramarua Catchment group exemplifies how local collaboration, expert guidance from Dr Whatley, and innovative tools like eDNA are delivering significant benefits for waterway health and building resilience for future generations in the area.<\/p>\n
The group will conduct further eDNA testing across the catchment in March 2027, thanks to its valuable insights.<\/p>\n","protected":false},"excerpt":{"rendered":"Over the past two years (2024 and 2025), eDNA results have been encouraging and informative. In 2024, approximately…\n","protected":false},"author":2,"featured_media":522676,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[7501,258934,2840,28119,95,58941,154288,11586,258936,53499,2841,59194,13574,1667,273,43630,1874,8243,209,4441,134,54448,258935,685,258932,258933,216845,2510,111,43,139,5974,69,1319,239096,25443,4993,8205,1517,66425,147,3649,48877,11408,165,2846,17249,376,1316,406],"class_list":["post-522675","post","type-post","status-publish","format-standard","has-post-thumbnail","category-environment","tag-7501","tag-258934","tag-across","tag-amp","tag-and","tag-assemble","tag-catchment","tag-coast","tag-communitydriven","tag-comprehensive","tag-country","tag-dynamics","tag-efforts","tag-energy","tag-environment","tag-flow","tag-found","tag-freshwater","tag-group","tag-habitat","tag-health","tag-indicators","tag-kkahi","tag-last","tag-mangatangi","tag-maramarua","tag-mmc","tag-multiple","tag-new-zealand","tag-news","tag-newzealand","tag-nutrient","tag-nz","tag-picture","tag-proactive","tag-progressing","tag-quality","tag-rare","tag-reveals","tag-rivers","tag-science","tag-species","tag-steadily","tag-testing","tag-their","tag-them","tag-visited","tag-water","tag-when","tag-wildlife"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/522675","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=522675"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/522675\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/522676"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=522675"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=522675"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=522675"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}